A Protocol for Housing Mice in an Enriched Environment

The goal of this procedure is to provide details necessary for housing and maintaining animals in environmental enrichment, which produces robust metabolic and anti-cancer effects in mice. This is accomplished by first setting up the enriched housing environment in a large bin with objects such as wheels, running sources, hutches, tubing, logs, and cages. The second step is to introduce the animals to the novel environment.

Next, the enriched environment is maintained by changing the location and type of objects in the bin and providing fresh food and water on a regular basis. The final step is to clean the objects that were replaced in the environment so they're ready to be exchanged in the future. Ultimately, upon euthanasia and analysis of animal tissues.

This technique of environmental enrichment shows decreased adiposity, increased energy expenditure resistance against diet induced obesity, and a white to brown fat phenotypic switch by activating the hypothalamic sym neural adipocyte axis. This method describes details regarding the setup of an enriched environment for laboratory rodents that enhances resistance to cancer and metabolic diseases. First, spray and wipe down the inside of a large enrichment bin with sporicidin disinfectants.

Following the manufacturer's instructions, wipe off the bin with 30%ethanol or tap water soaked paper, towel, and dryer with a paper towel to get rid of any scent from the previous disinfectant. Use plastic tubing igloos with SOR type wheels and other various plastic hutcher like toys in the enriched environment. Wash these toys as before, use metal running wheels that have been washed as before.

If the paint on the wheel starts to fade so that the wheel becomes noisy when the animals run on it, apply a small amount of petroleum jelly to where the wheel and axle connect. Use wooden logs in the enriched environment. Clean the logs by removing any bedding or other debris by hand.

Then sterilize the logs by autoclaving them on a dry cycle or textile cycle, which reaches a temperature of 121 degrees Celsius for 15 minutes. Use clean feeding cages between dimensions of 29 centimeters by 18 centimeters by 12.5 centimeters and 30.5 centimeters by 19 centimeters by 14 centimeters to hold. A feeding and drinking wire rack cuts a hole at least five centimeters in diameter out of the front bottom of the cage for the mice to enter and exit.

To begin. For one quarter inch corncob laboratory animal bedding into the clean to large enrichment bin to a depth of two to 2.5 centimeters. Next, place two or three of the previous aortic clave logs in one corner of the bin to sequester an area of around 1, 225 centimeter square.

Then in the area sequestered by the logs, place three glues with SOR wheels on top. Ensure that the wheels have room to spin freely. Now piece together the plastic tubing so that multiple arms branch out from the central connecting piece.

Place this tubing in the middle of the bin at two corners of the bin. Place a feeding cage filled with the same bedding as the bin. The hole in the front of each feeding cage should be facing towards the center of the bin.

Place a food and water wire containing mouse chow on top of each feeding cage. Add the water bottle. Place an 11.5 centimeter wheel, a 20.5 centimeter wheel, and a 28 centimeter wheel into the bin.

Then place four to five more plastic hutch like toys or tunnels throughout the enrichment bin. Cover the bin with micro isolator filter paper and use binder clips to clip the filter paper to the bin. When placing animals into the enrichment bin from a standard cage, place the cage in the bin on its side so that the animals can move freely from the standard cage to the enrichment bin.

Do not allow the nesting materials to be transferred into the enrichment bin. 10 to 20 animals with the same age, gender, and genetic strain can be housed in the enriched environment at one time. Ensure that the animals are observed daily for signs of illness or distress.

If necessary, gently handle the animals to further inspect their condition twice a week. Check the food and water levels, ensuring that the food and water will last for the next two days. Also, straighten up the running wheels and enrichment toys so that they're spread out and can be easily used.

Replace any enrichment items that are dirty once a week, ideally when the mice are removed from the environment. For experimental purposes, remove the feeding cages and wire racks and replace with clean cages and racks filled with fresh food. Replace the water bottles with clean water bottles.

Crucially rearrange the enrichment items so that the key aspects of the setup are preserved, but the enrichment items are placed differently.Spot. Check the rest of the large enrichment bin and clean if necessary. By scooping out dirty litter and spreading down new clean bedding once every two weeks.

When performing the weekly husbandry, wash the toys by hand or by sending them through the cage wash. Every month, clean the majority of the litter out by removing enrichment toys and feeding cages and scooping out the litter. Replace with fresh litter ensuring that there are two centimeters of bedding in all areas of the cage once every three months or as required by your animal protocol, remove all bedding and toys and disinfect the enrichment bin by washing as before house control Group animals on the same 12 hour light dark cycle.

As the mice in the enriched environment in micro isolated cages, provide the same corn cob bedding in the control cage as in the enriched environment, and add a four centimeter by four centimeter nest lit with a maister maker nest housed three to five mice of the same gender in a regular mouse cage. Do not provide any toy tube or hutch in the cage. Include a wire rack in the cage for holding food and a water bottle if the cage is not hooked up to an automatic watering system.

Monitor the health of the animals daily, ensuring that the animals have plenty of food and water. Replace or clean the cages, feeding wires, food and water. Once a week, clean the cages and wire racks as before.

Three week old male mice were housed in an enriched environment or control cages for five weeks prior to tumor subcutaneous inoculation with 10 to the five cells per animal. The results show B 16 melanoma tumor weights as 17 days after inoculation. Each group consisted of 10 animals.

The asterisk represents a P-value of less than 0.05 calculated by students'T-test here. Three week old mice was subjected to environmental enrichment for six days. Six days in an enriched environment, decreased retroperitoneal, white adipose tissue, fat pad weight.

This graph shows that six days in an enriched environment, decreased brown adipose tissue, epidermal white adipose tissue, and retroperitoneal white adipose tissue, fat pad weights relative to body weight. The next two graphs share results from mice housed in an enriched environment for four weeks as seen here, four weeks in environmental enrichment, decreased fat pad weights in all fat types except for brown adipose tissue. Four weeks in environmental enrichment, decreased fat pad weights relative to body weight for all fat types except brown adipose tissue.

After watching this video, you should have a good understanding of how to set up and maintain an enriched environment that induces anti-cancer and anti-obesity effects and mice.