Name: caring for research mice and rats
Uploaded: 2016-09-14T17:37:02.000Z
Duration: 13 min 24 s
Channel: JoVE

K12 Standards

new-york-state-science-learning-standards

New York State Science Learning Standards

High School

Life Science

Structure and Function

HS-LS1-2.

Basic Care Procedures

All animal procedures described here must be conducted in accordance with institutional animal ethics guidelines and approved by IACUC. All procedures must follow the principles of the 3Rs&#8212;Replacement, Reduction, and Refinement&#8212;and must be performed by trained personnel. 
1. Handling immunocompetent (conventional) mice
It has been demonstrated that immune disorders of mice are very similar to those in humans. As these animals have limited immunological capabilities, procedures in the handling and care of these animals have been designed to minimize the risk of infectious disease through the use of engineering controls, personal protective equipment for the animal care staff, and standard operating procedures; these mitigate contamination of caging and other equipment with which the animals are in contact.
<ol>
	<li>Unpacking from shipping containers: Receiving animals from other institutions or animal vendors poses a risk to the animals already housed within the animal facility. During transit, the animal transport boxes can come in contact with pathogenic agents. Therefore, proper procedure should be performed when unpacking the shipping containers.
	<ol>
		<li>Minimal Personal Protective Equipment (PPE) requirements are gloves, clean lab coat or scrubs, a particulate mask, and safety glasses when handling the animals.</li>
		<li>Select the appropriate cage, including the wire bar lid and the barrier top. The cage should be furnished with appropriate bedding and nesting materials. All caging should be prepared and placed in the receiving area prior to the arrival of the animals.</li>
		<li>Upon arrival, the transport boxes are placed in a secure and temperature controlled room. Then, examine the container for damage.</li>
		<li>Disinfect the outer surfaces of the shipping container with an appropriate disinfectant to destroy any harmful pathogens. Make sure that the disinfectant is in contact with the box in accordance with the manufacturers recommendations, usually 15-30 minutes.</li>
		<li>Place the container in an Animal Transfer Station (ATS). The ATS provides HEPA-filtered airflow within the hood that provides allergen protection by creating a vacuum air barrier between the user and work zone. This ensures minimal exposure to animal hair/dander and cage bedding material. The unidirectional air also protects the animals from the surrounding room air, minimizing the chance of contamination.</li>
		<li>Once the shipping container is opened, assess the overall health of the animals. Make a note of any injured or ill animals.</li>
		<li>Place the animals into the assembled cages in the proper group sizes. The grouping should be in accordance with the space regulations, and the experimental protocol to which they will be assigned.</li>
		<li>Cover the cage with the wire bar lid. Secure the divider on the wire bar lid to create two areas on the lid.</li>
		<li>Select the appropriate food and place the food on one side of the wire bar lid. Leave the second side open to allow for better circulation of air.</li>
		<li>Water will be provided via water bottles or an automatic watering system. Water bottles are used for newly weaned mice to ensure that they are able to maintain their hydration levels. For IVC caging with automatic watering, charge the watering tube prior to placing it on the rack.</li>
		<li>Place the cage on a rack. If using IVCs, check that the cage is fully engaged onto the rack, and that the sipper tube is secured to the watering system.</li>
	</ol>
	</li>
	<li>Cage changing conventional mice
	<ol>
		<li>Animal cages are changed in an ATS. The ATS is disinfected at the end of each session.</li>
		<li>Only one cage can be opened at a time.</li>
		<li>Caging prepared with the appropriate bedding and nesting materials is brought into the animal room. A small number of cages are placed in the ATS.</li>
		<li>IVC cages with internal sipper tubes must be charged to force water into the sipper to remove the dead space of air in the sipper tube. If not properly charged, the mice may not be able to provide enough pressure on the sipper tube to remove the air from it.</li>
		<li>Minimal Personal Protective Equipment (PPE) requirements are gloves, clean lab coat or scrubs, a particulate mask, and safety glasses when handling the animals.</li>
		<li>A cage of animals to be changed is placed into a new cage, and then in the ATS.</li>
		<li>Animals are transferred using appropriate handling techniques, such as cupping or tunnel handling, to minimize stress. Gloves are either changed between cages or between groups of mice. Gloves can also be disinfected with a nontoxic chemical between cages.</li>
		<li>It has been demonstrated that transferring the nesting area of the mice into a clean cage assists with the transition into the clean cage, especially for group-housed males. Other enrichment items are also transferred to the new cage.</li>
		<li>Once the cage top or feeder is placed in the new cage, food is added.</li>
		<li>The barrier top is placed on the new cage and the cage is returned to the rack.</li>
		<li>IVC cages must be properly docked into the rack to ensure that the air and water valves are engaged.</li>
	</ol>
	</li>
</ol>
2. Handling immunocompromised mice
<ol>
	<li>Unpacking from shipping containers
	<ol>
		<li>Immunocompromised animals must be unpacked under sterile conditions. All individuals handling immune deficient mice must wear a steam sterilized gown, mask, hair bonnet, and sterile gloves. Aseptic technique should be used at all times when handling these animals.</li>
		<li>All equipment and caging should have been sterilized by steam, UV radiation, or chemically sterilized with a soak in disinfectant&#160; for at least 30 minutes There are two options for sterile caging: standard caging that has been wrapped and steam sterilized, or caging that is sterilized-usually through irradiation-by the vendor. These cages are disposable units.</li>
		<li>Prior to manipulating mice under the laminar flow hood, the hood is sprayed with an appropriate disinfectant with the blower operating. The hood blower should remain on at all times to maintain the sterile environment. After each use, the hood is sprayed with a disinfectant and wiped of all debris and again sprayed with 70% ethanol..</li>
		<li>Optimally, two people are required for the proper receiving of the immunocompromised mice: one to handle the animals using aseptic techniques (the sterile technician), and one that will handle contaminated items (the nonsterile technician). The nonsterile person should still wear a clean, long-sleeved gown; lab coat or smock; mask; bonnet; and sterile gloves to prevent contamination of the sterile interior should they need to reach into the hood.</li>
		<li>Prepare a laminar flow hood as previously described. It is preferable to have a hood dedicated for immunocompromised animals. It is recommended that hood be equipped with ultraviolet (UV) sterilization lights that can be used to sterilize the interior of the hood between uses. A timer is utilized to ensure that the surface of the hood has adequate exposure to the UV rays.</li>
		<li>The exterior of all supplies that are placed into the hood are sprayed with an appropriate disinfectant, including the outer packaging of food, water, and caging.</li>
		<li>Shipping containers are sprayed with an appropriate disinfectant before they are placed in the hood. Once placed in the hood, they are to remain unopened for 15-30 minutes.</li>
		<li>The designated animal handler opens the sterile food and water under the hood.</li>
		<li>The nonsterile technician opens the shipping box under the hood. Care must be taken by the nonsterile technician to avoid contact with the inner surfaces of the hood and the inside of the shipping box.</li>
		<li>The animal handler opens the sterile cage, and prepares the cage by placing food and water onto the cage top. The mice are then removed from the shipping box and placed into the sterile cage.</li>
		<li>Animal condition is noted by the sterile animal handler. Any animals that appear ill or have obvious injuries will be segregated. All cages marked with animals requiring veterinary attention will be placed for handling, cage changing, or experimental manipulation last, to reduce potential contamination of other animals.</li>
		<li>The nonsterile person will remove the populated cage from the hood. Cages can be placed on a standard rack as static cages, or on a ventilated rack as IVCs. In the IVCs, the mice should be provided with additional nesting materials to assist with thermal regulation.</li>
		<li>The animal handler should change gloves after each shipping container to avoid possible cross contamination of groups of animals. The shipping container number is recorded on the cage card to track the origin of the animals in the event of illness.</li>
		<li>Unused supplies can be saved for future use provided the original container can be resealed. Unused food is removed from the room.</li>
		<li>Mice should undergo a minimum one week acclimation period prior to experimental use.</li>
	</ol>
	</li>
	<li>Cage changing for immunocompromised mice
	<ol>
		<li>The mouse cages are changed at least once weekly, or more often if deemed necessary.</li>
		<li>Steps for hood preparation, cage preparation, and personnel PPE are the same as for the unpacking of the animals.</li>
		<li>Animals are either transferred by cup handling or tunnel handling, to minimize stress. The designated animal handler should reglove after every 5-10 cages, if the gloves are torn or contaminated, or if an animal appears ill.</li>
		<li>Any cages with animals appearing sick will be placed at the end of the cage changing order, to avoid possible exposure of healthy animals to pathogens or contaminants.</li>
		<li>If food and/or water must be added to the cage before the next scheduled cage change, it must be done aseptically under the prepared hood.</li>
	</ol>
	</li>
</ol>
Key Terms and Definitions 
Housing/Caging 
Mice and rats are primarily housed in shoebox-type caging with a solid bottom that contains bedding material. The typical shoebox mouse cage provides 75 square inches of floor space, which is adequate for a maximum of five adult mice. However, the experimental design may call for groups of four mice. In this case, the mice should be housed upon receiving in groups of four, to avoid the disruption of social groups when the experiment begins. In general, rat caging allows for a maximum of two fully-grown adult animals. If the rats are to be housed long-term, they should be established in pair housing. The cages can be static or individually ventilated (IVC). Static cages are either covered with a wire bar lid or are settled onto a rack under a shelf that is then the top of the cage. Filter material is added over the cage top either as a bonnet over the wire bar lid, or as a sheet of filter paper over the rack shelves. IVCs are set up as a cage, wire bar lid, and bonnet that are placed on a rack that provides air flow into the cage. The use of IVCs eliminates the need to change the cage as often as static cages are changed. Standard cage systems provide a source of water and an area for food distribution.&#160; 
Water can be provided via a water bottle placed on the top of the cage or via a sipper tube that is a built in component of the animal cage. When the cage is engaged onto a rack, water is transported into the sipper tube for an automatic watering system that is designed to meet the needs of the animal throughout the animal facility. Caging must be properly prepared to provide proper care for the animals. There are either feeders placed within the animal cage, or a section of the wire bar lid is used for food storage. Food must be placed such that it is not soiled by the animals. The Guide for the Care and Use of Laboratory Animals (the &#34;Guide&#34;) states that all caging implements must be sanitized at least every 2 weeks. Some cages and accessories may need to be changed more often as dictated by the level of odor and ammonia in the enclosure. In general, the IVCs are scheduled for changing every two weeks unless there are four or more males or a female with a litter; those enclosures may require weekly changing. As cage changing is an opportunity for the mice to be exposed to pathogens, changing of the caging for immune deficient mice should be done as infrequently as possible. 
Diet 
There are many compositions of diets available with variations in protein, carbohydrate, and fat levels. Typically, feeds should be comprised of 15-19% protein, 44% carbohydrates, and 4-9% fat. Food with an increased fat content is often used for breeding colonies to enhance reproduction. As the food can be a source of contamination for immunocompromised mice, it must be either steam sterilized or irradiated. Food that is subjected to the autoclaving process must be specially formulated to withstand the process. However, the irradiation process does not alter the food contents. Water is another potential source of contamination for the immune deficient animals. Water should be processed either through an autoclave or filtration that includes the water passing through a UV filter. To steam sterilize water in an autoclave, individual bottles of water are covered with aluminum foil. Bottle lids with sipper tubes are sterilized separately in an autoclave bag. Automatic watering systems can be used with a series of filtration throughout the system that includes particulate filters and an ultraviolet light filter. 
Environment 
Environmental conditions within an animal care facility must be tightly controlled. Federal regulations and guidelines have established the standards for the care and handling of commonly used animals. Lighting, ambient temperature, humidity, and air flow are provided to meet the physiological needs of the animals. With the exception of the need for a slightly increased room temperature, the parameters for the immunocompromised animals are the same as those for conventional animals. The athymic nude animals also require additional bedding and shredded paper-type nesting materials in their cages to assist with thermoregulation. 
Animal rooms should be maintained at a temperature between 68-72&#176;F with a humidity level of 40-60%. Humidity levels below 40% can result in ringtail of mice and rats, a condition that causes the skin of the tail to dry to the point of it, constricting around the tail, which can lead to the tail sloughing. Lighting cycles should be set to avoid stressors to the animals caused by inappropriate photoperiods or light intensity. Normally, photoperiods are 12 hours on and 12 hours off. The lighting intensity should vary in accordance with the activity in the room. When technicians are working in the animal room, higher lighting levels can be used. However, the lighting should be lowered to approximately 325 lux once all activity is concluded. The lights should be on timers and the cycles verified through monitoring systems. As directed by the Guide, animal rooms must have a minimum of 10-15 air changes of 100% fresh air per hour. Air changes decrease microbes and odors in the animal room. In densely populated animal rooms, the number of air changes per hour may need to be increased. 
Environmental factors at the cage level include the caging type, the substrate used within the cage, the water delivery system, and the diet. Social housing is mandatory unless scientifically justified, or an animal is incompatible with all others. The provisions of environmental enrichment, such as paper huts and nesting materials, allow the animals to exhibit species-specific behaviors, which in turn decreases the stress level and increases the overall wellbeing of the animals. Nesting materials also provide a sleeping area that is saturated in calming pheromones that assists with the housing of multiple male mice in the same cage. The nesting area is moved to the clean cage upon cage changing to help prevent aggression in the males as they are introduced into a new environment. 
Questions that this video will help you answer 
The proper care and handling of animals used in biomedical research is crucial to the outcome of the experiments. Regulations and established guidelines dictate many of the practices used. However, additional measures are required for mice and rats that have immune deficiencies to mitigate accidental exposure to opportunistic pathogens. When practices adhere to established procedures, the health and wellbeing of the experimental animals is enhanced, and better experimental results are attained.

basic care procedures

Source: Kay Stewart, RVT, RLATG, CMAR; Valerie A. Schroeder, RVT, RLATG. University of Notre Dame, IN
Mice and rats account for a large proportion of the animals used in biomedical research. Ensuring their welfare is both an ethical responsibility and essential for scientific validity. There are general procedures that apply to the majority of these mice and rats, but some of the animals, such as the immunocompromised ones, require additional steps to be taken to sustain them for experimentation.
Commonly used immunocompromised mice include those that have naturally occurred in inbred mice and those that have been created through genetic engineering. The first immunocompromised mice used in research were &#34;nude&#34; mice. The BALB/c Nude (nu) mouse was discovered in 1966, within a BALB/c colony that was producing mice lacking both hair and a thymus. These athymic mice have an inhibited immune system that is devoid of T cells. The value of this animal was soon discovered for the use in studies of microbial infections, immune deficiencies, and autoimmunity. Although not as commonly used as the nude mouse, there is also a nude rat. The nude rat is T cell deficient and shows depleted cell populations in thymus-dependent areas of peripheral lymphoid organs. Another naturally occurring immune deficient mouse is the severe combined immunodeficiency mouse (SCID). These mice have a defect that impairs the production of functional B and T cells. With the inability to mount an adequate immune response, these mice can serve as host recipients for transplants of human cells. Several genetically-modified mouse strains with immune deficiencies are commercially available. The severity of the deficiency varies with the genetic modification; however, all of the immunocompromised mice and rats are handled similarly.

This manuscript will describe the care of both immunocompetent and immunocompromised animals. The housing, diet, environmental requirements, and handling will be discussed for both groups of animals

Source: Kay Stewart, RVT, RLATG, CMAR; Valerie A. Schroeder, RVT, RLATG. University of Notre Dame, IN
Mice and rats account for a large proportion of the ...

Since mice and rats account for a large proportion of animals used in biomedical research, ensuring their welfare is both an ethical responsibility and essential for scientific validity.&#160; 
Animal care procedures begin with receiving animals from shipping containers and continue through cage changing, appropriate housing, providing proper nutrition, and environmental management.&#160; 
These practices should be performed in accordance with institutional guidelines and the principles of the 3Rs, particularly refinement, to minimize stress and promote well-being.&#160; 
This video describes the standards and essential care procedures for laboratory animals.&#160; 
Receiving animals from other institutions poses a risk of introducing pathogens; therefore, proper procedures should be followed when unpacking shipping containers. 
Before handling any animals, it is important to wear the appropriate Personal Protective Equipment, or PPE.&#160; 
Minimum PPE includes a lab coat, gloves, safety glasses, and a surgical type mask, which helps reduce exposure to dust and allergens and minimizes the risk of contamination to the animals.&#160; 
The next step is to select appropriate cages for incoming animals. Then, furnish the cage with appropriate bedding and nesting materials, and place the prepared cages in the temperature-controlled receiving room prior to animal arrival. 
Upon shipment arrival, place the transport boxes in a secure area in the receiving room. Examine the container for any damage and disinfect the outer surfaces to reduce potential contamination.&#160; 
Ensure that the disinfectant remains in contact with the box, as per manufacturer&#39;s recommendations. Then, place the container in the Animal Transfer Station, or ATS. 
This station provides HEPA-filtered unidirectional airflow, which reduces airborne contaminants, protecting both personnel and animals. 
Next, open the shipping container and evaluate the overall health of the rodents. Any animals that appear injured or ill should be reported and managed according to institutional veterinary guidelines.&#160;&#160; 
After that, place them into the already assembled cage in the appropriate group sizes,&#160; based on species, sex, and compatibility, cover the cage with the wire bar lid, and secure the divider if required.&#160; 
Select the appropriate food and place it in the designated area of the cage. Lastly, add a water bottle to ensure adequate water supply. Remember, the ATS has to be disinfected at the end of each session, and the blower remains on during disinfection. 
For cage changing, place the two cages&#8212;a fresh cage with the appropriate bedding material and the used cage with the animals&#8212;in the ATS. Animals should be transferred using appropriate handling techniques, such as cupping or tunnel handling, to minimize stress.&#160; 
Only one cage of animals should be opened at a time. For male mice or females with a litter, it has been demonstrated that transferring the nesting area of the mice into the clean cage assists the animals with the transition.&#160; 
Once the cage top is placed on the new cage, transfer clean food from the old cage top to the new top and add more food if necessary.&#160; 
Next, place the barrier top, and return the cage to the rack. It is a good practice to change gloves between cages or between groups. 
For the unpacking of immunocompromised animals, aseptic conditions must be maintained. It is recommended to turn on the blower inside the hood before use to allow proper airflow to be established. 
Like for immunocompetent animals, upon shipment arrival spray the container with an appropriate disinfectant and leave it unopened as per manufacturer&#39;s recommendations. 
At the ATS designated for immunocompromised mice, disinfect the laminar flow hood using an appropriate disinfectant prior to manipulating animals.&#160; 
Ideally two personnel may be involved in this unpacking activity-a sterile technician handling animals aseptically, and a non-sterile technician handling contaminated items. Both should wear appropriate PPE. 
Before opening the shipping container inside the hood, place all the supplies and caging in the hood and disinfect their exterior using an appropriate disinfectant.&#160; 
Sterilized caging can include either reusable autoclaved cages or sterile, ready-to-use disposable cages. 
The non-sterile person unwraps the sterile cage and aseptically passes it to the animal handler, who then removes the bonnet and the wire bar lid and places them in the hood without contaminating the inner surfaces.&#160; 
The animal handler should change outer gloves as needed to maintain aseptic technique. 
Subsequently, the sipper tube on the cage is filled with water at the station located in the hood. Lastly, the animal handler places the animal into the cage, secures it with the wire bar lid, adds food and sets the bonnet in place. Note that the hood blower should remain on at all times to maintain&#160; aseptic conditions. 
At the end, the non-sterile person removes the populated cage from the hood and places it on an appropriate rack.&#160; 
Now let&#39;s discuss appropriate housing conditions for the animals, which is another important aspect of providing essential care.&#160; 
Mice and rats are primarily housed in shoebox type caging with a solid bottom containing bedding material. 
The typical mouse cage provides 75 square inches of floor space, which can accommodate up to 4-5 adult mice, depending on strain, sex, and compatibility. 
On the other hand, a rat cage has an area of 142 square inches and can accommodate up to 2 adult rats,&#160; depending on strain and compatibility. Housing should also allow rats to exhibit normal postures, including the ability to rear.&#160; 
Static cages are usually covered with a wire bar lid and filter material is added over the cage top as a bonnet. Individually ventilated cages, or IVCs, also have a wire bar lid and bonnet, but they are placed on a rack that provides airflow into the cage.&#160; 
This can reduce the frequency of cage changes compared to static cages, which may be beneficial for immunocompromised animals. 
All caging systems have a provision for food and water supply. There are either feeders placed within the animal cage or a section of the wire bar lid is used for food storage. Food must be placed such that it is not soiled by the animals. 
Water is usually supplied via a water bottle placed on the top of the cage, or via an automatic watering drinking valve that is a built-in component of the animal cage.&#160; 
For the drinking valve option, when the cage is engaged onto a rack, water is delivered through an automated valve system connected to a central supply that is designed to meet the needs of the animal throughout the animal facility. 
The Guide for the Care and Use of Laboratory Animals recommends that caging implements be sanitized regularly, typically about every 2 weeks.&#160; 
Some cages and accessories may need to be changed more often as dictated by the level of odor and ammonia in the enclosure. 
Proper food and water supply are essential for animal care. There are many commercially available feeds with variable protein, carbohydrate, and fat compositions. 
Feed composition may vary depending on the species, strain, and study requirements. For immunocompromised animals, feed is typically provided in a sterilized form according to institutional guidelines. 
Water should be provided in a form that is safe and appropriate for the animals, with treatment or sterilization applied as needed according to institutional guidelines. 
Standard environmental conditions are also essential for maintaining animal welfare. 
At the cage level, animals should be socially housed unless scientifically justified for single housing or if an animal is incompatible with all others.&#160; 
Enriching the environment with paper huts and nesting materials allows the animals to exhibit species-specific behaviors such as nest building and burrowing, which in turn decreases the stress level and increases the overall well-being of the animals.&#160; 
Nesting materials also provide a familiar sleeping area with scent cues that can assist with housing multiple male mice in the same cage.&#160; 
As mentioned previously, moving the nesting area to the clean cage during cage changing helps reduce aggression, especially in males, as the animals are introduced into a new environment.&#160; 
At the room level, the temperature for mice and rats is typically between 68 and 79&#176;F, according to institutional guidelines. The room humidity level should be 30-70%, as lower levels can result in a condition known as ringtail. The third room parameter is lighting. This includes light intensity and light-dark cycles.&#160; 
Normally, the animal room is set to a 12-hour light/12-hour dark cycle. Lighting intensity should be adjusted according to the activity in the room and maintained at levels appropriate for the species and strain when the room is unoccupied.&#160; 
Lastly, airflow within the room should also be carefully controlled. Ventilation should provide an appropriate number of air changes per hour, according to institutional standards, to help reduce odors and microbial load in the animal room. 
Lastly, let&#39;s see how researchers are using this knowledge about lab animals housing, diet and environment preferences in their experiments.&#160; 
As discussed earlier, lab animals generally exhibit nest-building behavior, which reduces stress, and researchers have used this as an indicator of animal welfare is associated with reduced stress and can serve as an indicator of animal well-being. This behavior can be influenced by environmental conditions such as ambient temperature, highlighting the importance of maintaining appropriate housing conditions to support animal welfare. 
You&#39;ve just watched JoVE&#39;s introduction to essential care procedures for mice and rats. You should now have a better understanding of the measures one should take to ensure that the environment and handling of these animals does not cause any harm to animal&#39;s health and you should also know how researchers can modify these parameters to achieve different scientific goals.

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caring for research mice and rats

Research mice and rats need careful housing, feeding, and handling. These animals make up over 90% of the animals used for biomedical research, so their care can strongly affect experiment results. Both immunocompetent animals, which have a normal immune response, and immunocompromised animals need proper support during studies.

Some research animals have weakened immune systems and need extra steps to stay healthy. Common examples include naturally occurring immunocompromised mice and mice created through genetic engineering. The first immunocompromised mice used in research were nude mice. The BALB/c Nude, or nu, mouse was discovered in 1966 in a BALB/c colony that included mice lacking both hair and a thymus.

These athymic mice, meaning mice without a thymus, have an inhibited immune system that lacks T cells. Researchers quickly found value in nude mice for studies of microbial infections, immune deficiencies, and autoimmunity. A nude rat also exists. It is T cell deficient and has depleted cell populations in thymus-dependent areas of peripheral lymphoid organs.

Another naturally occurring immune-deficient model is the severe combined immunodeficiency, or SCID, mouse. These mice have a defect that prevents the production of functional B and T cells. Because they cannot mount an adequate immune response, they can be used as host recipients for transplants of human cells. Several genetically modified mouse strains with immune deficiencies are also available commercially.

The exact severity of immune deficiency can vary with the genetic modification. Even so, immunocompromised mice and rats are handled in similar ways. Care for both immunocompetent and immunocompromised animals includes attention to housing, diet, environmental needs, and handling. These basic steps help support the animals during research.

Caring for Research Mice and Rats

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Research mice and rats need careful housing, feeding, and handling. These animals make up over 90% of the animals used for biomedical research, so their care can strongly affect experiment results. Both immunocompetent animals, which have a normal immune response, and immunocompromised animals need proper support during studies. Some research animals have weakened immune systems and need extra steps to stay healthy. Common examples include naturally occurring immunocompromised mice and mice...

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considerations for rodent surgery 

Aseptic Steps in Rodent Survival Surgery

Aseptic technique is essential for rodent survival surgery. It is used to keep the surgical site as clean as possible and to reduce contamination during the procedure. This approach includes patient preparation, surgeon preparation, and sterilization of instruments and other supplies. It also depends on a clean, controlled environment. Careful planning before surgery helps set up these steps for success. During the operation, animals need close monitoring. After the surgery, postoperative...

diagnostic necropsy and tissue harvest

Rat Necropsy for Tissue Collection

Rat necropsy is a key step for collecting organs and tissues at the end of many animal studies. These final samples are used for data collection time points and later testing. Because the samples are used for analysis, the way they are taken can affect sample quality. Careful collection methods help preserve the organs and tissues for testing. The method of euthanasia, or the procedure used to humanely end the animal's life, can also affect sample quality. This article outlines proper necropsy...

sterile tissue harvest

Aseptic Organ Collection in Rats and Mice

Aseptic organ collection in rats and mice is used to keep harvested tissues free from contamination. The process is important when tissues will be used for cell and tissue cultures. It also supports later protein and RNA analysis, as well as metabolic profiling of tissues. The transcript connects this work to the 3 R's, which were introduced in 1959 by W.M.S. Russell and R.L. Burch in The Principles of Humane Experimental Technique. The 3 R's are replacement, reduction, and refinement in the...

early intervention and pain management

Early Intervention and Pain Management

All animal procedures described here must be conducted in accordance with institutional animal ethics guidelines and approved by IACUC. All procedures must follow the principles of the 3Rs—Replacement, Reduction, and Refinement—and must be performed by trained personnel.  Monitoring Animals for Signs of Pain and Distress Recognizing early signs of pain is essential for ethical animal research. Animals are routinely monitored using behavioral, physical, and physiological parameters that reflect...

humane euthanasia and confirmation of death in rodents

Humane Euthanasia and Confirmation of Death in Rodents

All animal procedures described here must be conducted in accordance with institutional animal ethics guidelines and approved by IACUC. All procedures must follow the principles of the 3Rs—Replacement, Reduction, and Refinement—and must be performed by trained personnel. Humane endpoints in rodents are predefined clinical, behavioral, or physiological indicators that signal an animal is experiencing significant pain, distress, or declining health. When these signs are observed, timely...

habituation and positive reinforcement for rodent handling

Habituation and Positive Reinforcement for Rodent Handling

All animal procedures described here must be conducted in accordance with institutional animal ethics guidelines and approved by IACUC. All procedures must follow the principles of the 3Rs—Replacement, Reduction, and Refinement—and must be performed by trained personnel. Habituation and positive reinforcement are refinement strategies that help reduce stress during routine handling and experimental procedures in rodents. These approaches improve animal welfare, encourage voluntary cooperation,...

breeding management in rodent studies

Breeding Management in Rodent Studies

All animal procedures described here must be conducted in accordance with institutional animal ethics guidelines and approved by IACUC. All procedures must follow the principles of the 3Rs—Replacement, Reduction, and Refinement—and must be performed by trained personnel. Breeding management supports the 3Rs by minimizing unnecessary animal production and ensuring that only the number of animals required for a study is generated. Effective breeding strategies help reduce surplus animals and...

transport and acclimatization of rodents for research

Transport and Acclimatization of Rodents for Research

All animal procedures described here must be conducted in accordance with institutional animal ethics guidelines and approved by IACUC. All procedures must follow the principles of the 3Rs—Replacement, Reduction, and Refinement—and must be performed by trained personnel. Transporting rodents for research requires procedures that minimize stress and maintain animal welfare during movement to minimize the influence on experimental outcomes. Transport cages should provide adequate ventilation,...

environmental enrichment for rodents

Environmental Enrichment for Rodents

All animal procedures described here must be conducted in accordance with institutional animal ethics guidelines and approved by IACUC. All procedures must follow the principles of the 3Rs—Replacement, Reduction, and Refinement—and must be performed by trained personnel. Environmental enrichment involves objects and practices that encourage natural behaviors, improve psychological well-being, and promote better welfare in laboratory rodents. Environmental enrichment should be tailored to the...

rodents

Learn how research mice and rats are housed, fed, and handled, including nude and SCID models used in studies of infection, immunity, and transplants.

Caring for Research Mice and Rats | JoVE K12

HS-LS1-3.

Kay Stewart

Valerie A. Schroeder

University of Notre Dame

Overview

Unpacking and Cage Changing Procedures

Housing

Diet

Environment

Applications

Summary

Characteristics of Life

Biology is a natural science that studies life and living organisms, including their structure, function, development, interactions, evolution, ...

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Cell Structure

Background
Cells represent the most basic biological units of all organisms, whether it be simple, single-celled organisms like bacteria, or large, ...

Visualizing Onion and Cheek Cells
ExpandImmediately before the experiment, wash and peel onion bulbs for the class.
Remove the entire brown outer skin and ...

Visualizing Onion and Human Cells
ExpandIn this experiment you will prepare different types of cells from a plant and animal, onion and human ...

What are Cells?

Cell Diversity

The concept of a cell started with microscopic observations of dead cork tissue by Robert Hooke in 1665. Hooke coined the term &#34;cell&#34; based on the ...

Cytoplasm

The cytoplasm consists of organelles and a framework of protein scaffolds called the cytoskeleton suspended in an aqueous solution, the cytosol. The ...

The Nucleus

The nucleus is a membrane-bound organelle that acts as a control center in a eukaryotic cell. It contains chromosomal DNA, which controls gene expression ...

The Central Dogma

The DNA Helix

Nucleic Acids

DNA as a Genetic Template

Structure of a Gene

A gene is the fundamental unit of heredity. Every individual has two copies of each gene, one inherited from each parent. Although most people contain the ...

Chromosome Structure

Base-pairing and DNA Repair

What is Gene Expression?

A gene is a stretch of DNA that serves as the blueprint for functional RNAs and proteins. Since DNA is comprised&#160; of nucleotides and proteins are ...

RNA Structure

The basic structure of RNA consists of a string of ribonucleotides attached by phosphodiester bonds. Although most RNA is single-stranded, it can form ...

Types of RNA

Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs perform diverse ...

Transcription

Transcription is the synthesis of RNA from a DNA sequence by RNA polymerase. It is the first step in producing a protein from a gene sequence. ...

Translation

Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes ...

Ribosomes

Ribosomes translate genetic information encoded by messenger RNA (mRNA) into proteins. Both prokaryotic and eukaryotic cells have ribosomes. Cells that ...

Protein and Protein Structures

Proteins: From Genes to Degradation

From DNA to Protein

The flow of genetic information in cells from DNA to mRNA to protein is described by the central dogma, which states that genes specify the sequence of ...

Protein Folding

Proteins are chains of amino acids linked together by peptide bonds. Upon synthesis, a protein folds into a three-dimensional conformation, critical to ...

An Overview of Gene Expression

Gene expression is the complex process where a cell uses its genetic information to make functional products. This process is regulated at multiple ...

an-introduction-to-caenorhabditis-elegans

An Introduction to Caenorhabditis elegans

Caenorhabditis elegans is a microscopic, soil-dwelling roundworm that has been powerfully used as a model organism since the early 1970&rsquo;s.  It was ...

An Overview of Genetic Analysis

An organism&#8217;s physical traits, or phenotype, are a product of its genotype, which is the combination of alleles (gene variants) inherited from its ...

An Introduction to Cell Death

Necrosis, apoptosis, and autophagic cell death are all manners in which cells can die, and these mechanisms can be induced by different stimuli, such as ...

An Overview of Genetic Engineering

Genetic engineering &#8211; the process of purposefully altering an organism&#8217;s DNA &#8211; has been used to create powerful research tools and model ...

An Introduction to Cell Division

Cell division is the process by which a parent cell divides and gives rise to two or more daughter cells. It is a means of reproduction for single-cell ...

An Overview of Genetics and Disease

Many human diseases are associated with mutations or variations in genetic sequences. Some of these genetic variants are heritable, passed down from ...

an-introduction-to-cellular-and-molecular-neuroscience

An Introduction to Cellular and Molecular Neuroscience

Cellular and molecular neuroscience is one of the newest and fastest growing subdisciplines in neuroscience. By investigating the influences of genes, ...

Annexin V and Propidium Iodide Labeling

Staining with annexin V and propidium iodide (PI) provides researchers with a way to identify different types of cell death&#8212;either necrosis or ...

an-introduction-to-developmental-genetics

An Introduction to Developmental Genetics

Development is the complex process through which a single-celled embryo transforms into a multicellular organism. Developmental processes are guided by ...

Bacterial Transformation: Electroporation

The term &#x201C;transformation&#x201D; refers cellular ingestion of foreign DNA.  In nature, transformation can occur in certain types of bacteria.  In ...

an-introduction-to-molecular-developmental-biology

An Introduction to Molecular Developmental Biology

Molecular signals play a major role in the complex processes occurring during embryonic development. These signals regulate activities such as cell ...

bacterial-transformation-the-heat-shock-method

Bacterial Transformation: The Heat Shock Method

Transformation is the process that occurs when a cell ingests foreign DNA from its surroundings. Transformation can occur in nature in certain types of ...

an-introduction-to-saccharomyces-cerevisiae

An Introduction to Saccharomyces cerevisiae

Saccharomyces cerevisiae (commonly known as baker&rsquo;s yeast) is a single-celled eukaryote that is frequently used in scientific research.  S. ...

Cell Cycle Analysis

Cell cycle refers to the set of events through which a cell grows, replicates its genome, and ultimately divides into two daughter cells through the ...

An Introduction to Transfection

Transfection is the process of inserting genetic material, such as DNA and double stranded RNA, into mammalian cells. The insertion of DNA into a cell ...

Chromatin Immunoprecipitation

Histones are proteins that help organize DNA in eukaryotic nuclei by serving as &#8220;scaffolds&#8221; around which DNA can be wrapped, forming a complex ...

An Overview of Epigenetics

Since the early days of genetics research, scientists have noted certain heritable phenotypic differences that are not due to differences in the ...

community-dna-extraction-from-bacterial-colonies

Community DNA Extraction from Bacterial Colonies

Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba - The University of Arizona
Demonstrating Author: Luisa Ikner
Traditional methods of analysis ...

Cytogenetics

Cytogenetics is the field of study devoted to chromosomes, and involves the direct observation of a cell&#8217;s chromosomal number and structure, ...

embryonic-stem-cell-culture-and-differentiation

Embryonic Stem Cell Culture and Differentiation

Culturing embryonic stem (ES) cells requires conditions that maintain these cells in an undifferentiated state to preserve their capacity for self-renewal ...

DNA Gel Electrophoresis

DNA gel electrophoresis is a technique used for the detection and separation of DNA molecules. An electric field is applied to a gel matrix comprised of ...

Enzyme Assays and Kinetics

Enzyme kinetics describes the catalytic effects of enzymes, which are biomolecules that facilitate chemical reactions necessary for living organisms. ...

DNA Ligation Reactions

In molecular biology, ligation refers to the joining of two DNA fragments through the formation of a phosphodiester bond.  An enzyme known as a ligase ...

explant-culture-for-developmental-studies

Explant Culture for Developmental Studies

Explant culture is a technique in which living cells or tissues are removed from an embryo for continued development outside of the organism. This ex vivo ...

DNA Methylation Analysis

Methylation at CpG dinucleotides is a chemical modification of DNA hypothesized to play important roles in regulating gene expression. In particular, the ...

Expression Profiling with Microarrays

Microarrays are important tools for profiling gene expression, and are based on complementary binding between probes that are attached to glass chips and ...

Density Gradient Ultracentrifugation

Density gradient ultracentrifugation is a common technique used to isolate and purify biomolecules and cell structures. This technique exploits the fact ...

Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.

HS-LS1-1.

Caring for Research Mice and Rats

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