Name: Urinary Tract Infection in a Small Animal Model: Transurethral Catheterization of Male and Female Mice (Video) | JoVE Journal
Uploaded: 2017-12-01T13:00:00.000+00:00
Duration: 10 min 23 s
Description: Learn transurethral catheterization for urinary tract infection research using male and female mice. This method enables comparative study of sex-based immune responses in bladder pathologies.

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5 minutes

We thank Dr Matthieu Rousseau for critical reading of the manuscript and the Laboratory of Dendritic Immunobiology for their helpful insights during the development of this protocol and project. This work was supported in part by funding from the European Union Seventh Framework Programme Marie Curie Action (PCIG11-GA- 2012-3221170, and the Immuno-Oncology LabEx (MAI).

Mouse experiments were conducted in accordance with approval of protocol number 2012-0024 by the Comit&#233; d&#39;&#233;thique en exp&#233;rimentation animale Paris Centre et Sud (the ethics committee for animal experimentation), in application of the European Directive 2010/63 EU.
1. Preparation of Catheters
<ol>
	<li>Prepare one pediatric intravenous-access cannula for each group of mice to be infected. Using the inbuilt spring mechanism, divest each cannula of its needle, as instructed by the manufacturer. Discard the needles, preserving only the plastic intravenous cannula.</li>
	<li>Sterilize catheters in a laminar flow hood for one ultraviolet (U.V.) cycle, typically 25 - 30 min. 
	Note: Catheters can be used for more than one mouse, however a new catheter should be used between experimental groups, sexes, or bacterial strains.</li>
</ol>
2. Preparation of Uropathogenic E. coli for Infection
<ol>
	<li>At least two days prior to infection, using a sterile inoculation loop, streak UPEC from a frozen bacterial stock onto a Luria Broth (LB) agar plate, containing antibiotics if appropriate. Incubate at 37 &#176;C overnight. Plates can be stored at 4 &#176;C for up to one week.</li>
	<li>In a 100 ml sterile Erlenmeyer flask, inoculate 10 ml LB, containing antibiotics if appropriate, with a single colony from the LB plate and incubate standing at 37 &#176;C overnight (approximately 16 - 18 hr). 
	Note: Standing cultures permit the expression of type 1 pili, which are necessary for infection23. Cultures grown shaking will have less efficient pili expression, and therefore, inconsistent rates of infection.</li>
	<li>Measure the optical density (OD)600 of the overnight culture and calculate the number of bacteria per ml using a pre-determined growth curve. As an example, for UPEC strain UTI89, OD600 = 0.35 is equivalent to 2 x 108 CFU per ml, thus, an overnight culture with an OD600 = 2.4 would be equivalent to 13.7 x 108 CFU per ml. Empirically determine the relationship between the OD600 and viable bacteria with every new strain employed for infection.</li>
	<li>Determine the amount of bacteria needed by considering the number of animals to be infected and that each mouse should receive approximately 107 colony-forming units (CFU) in 50 &#956;l PBS. Include in the calculation the ~130 &#181;l dead volume of the catheter and syringe nub and 100 &#181;l needed to determine the inoculum.
	<ol>
		<li>Spin the bacterial suspension in a tabletop microcentrifuge at 17,000 x g for 1 min and resuspend the resulting bacterial pellet at 2 x 108 CFU per ml in PBS. Serially dilute an aliquot of this suspension and plate on LB agar, with antibiotics if appropriate, to determine the exact inoculum for each infection.</li>
	</ol>
	</li>
	<li>Draw the bacterial inoculum into a 1 ml syringe and attach the catheter to the end of the syringe. Tap the syringe to remove any air and depress the plunger to fill the dead air space in the catheter before beginning the instillation.</li>
</ol>
3. Preparation of Mice
<ol>
	<li>Anesthetize mice via intraperitoneal injection of 100 mg/kg ketamine and 5 mg/kg xylazine. Supplemental heat can be provided.&#160;</li>
	<li>Ensure that each mouse is fully sedated by squeezing the footpad with medium pressure. Mice are fully sedated when they do not react and require 3 - 5 min to reach this state.</li>
	<li>Place mice supine and apply medium pressure to the lower abdomen to empty the bladder of urine. Full bladders feel like a pea under the skin between the ileac crests. 
	Note: Inhaled isoflurane has been used to catheterize female mice15,22, however, it has not been tested whether male mice are sufficiently anesthetized by inhaled isoflurane for this procedure.</li>
</ol>
4. Transurethral Instillation of Female Mice
<ol>
	<li>Using the non-dominant hand, place the thumb on the tail and a finger of the same hand on the abdomen of the mouse and apply gentle pressure in opposing directions to hold the mouse firmly in place.</li>
	<li>Place the tip of the catheter perpendicular to the mouse at the urethral orifice. With gentle pressure, slide the catheter into the urethra, until the hub meets the urethral orifice, while simultaneously lowering the syringe so that it is parallel to the working surface. The catheter requires no lubrication. Do not push or force the catheter into the urethra. The catheter should slide smoothly and easily into the urethra, with little to no resistance.
	<ol>
		<li>Before instilling the inoculum (step 4.3), once the catheter is in place, very gently pull the abdominal skin towards the head of the mouse with the finger from the non-dominant hand that is already on the abdomen of the mouse (step 4.1). If the catheter is in the urethra, the tissue composing the urethra orifice will not move, whereas if the catheter is incorrectly placed in the vagina, the tissue will move up and away from the catheter. This rapid test should be performed on each mouse.</li>
	</ol>
	</li>
	<li>When the hub of the catheter meets the urethral orifice, slowly dispense 50 &#181;l of the bacterial inoculum. A slow instillation rate minimizes vesicoureteral reflux into the kidney. Slowly remove the catheter to prevent leakage, over a count of 5. Place mice in their cages in a supine position.</li>
</ol>
5. Transurethral Instillation of Male Mice
<ol>
	<li>Place two thumb forceps cranially and caudally to the mouse&#39;s external genitalia. Retract the prepuce to fully expose the glans penis. Once the penis is externally positioned, release the thumb forceps.</li>
	<li>Reposition the forceps to stabilize the protruding penis perpendicular to the animal, holding the organ gently but tautly. Visualize the urethral meatus and carefully introduce the catheter into the small opening at the tip of the organ. Gently guide the catheter into the penis, toward the body of the mouse, maintaining gentle tension with the forceps. The catheter requires no lubrication. Do not force the catheter into the penis; the catheter should slide smoothly into the urethra, indicating correct placement.</li>
	<li>Once the hub of the catheter meets the tip of the penis, very slowly dispense 50 &#181;l of the inoculum, while maintaining the position of the penis. The quality of the instillation can be noted at this time according to a predetermined instillation quality score, such as that shown in Figure 2.</li>
	<li>Retract the catheter slowly, over a count of 5, to prevent leakage of the inoculum. Place mice in their cages in a supine position. Animals should begin to recover 30 - 45 min following administration of the anesthetic.</li>
</ol>
6. Determination of CFU in Infected Organs
<ol>
	<li>At predetermined time-points, sacrifice mice using approved standard operating procedures (e.g., cervical dislocation or carbon dioxide overdose). Moisten the abdomen thoroughly with 70% ethanol to minimize contamination by fur.</li>
	<li>Make an incision across the lower third of the mouse&#39;s abdomen of at least 2 cm using scissors and aseptically remove the bladder and any other desired organs, including but not limited to, kidneys, testis, seminal vesicles, or preputial glands, into 5 ml polypropylene snap cap tubes containing 1 ml sterile PBS. Keep all samples on ice.</li>
	<li>Homogenize the organs with a handheld homogenizer until almost no solid tissue remains, approximately 15 - 60 sec depending on the organ. Fat does not homogenize well, and is easily recognizable as shiny beige-white tissue. Discard fat prior to or following homogenization. Wash the homogenizer in ethanol followed by PBS between each experimental or organ group. 
	Note: Typically, use handheld homogenizers or bead mill homogenizers. While all of these systems have yielded similar results, as determined by direct comparison of bacterial CFU at 24 hr post-infection, the optimal conditions to homogenize host tissue while preserving bacterial viability should be determined empirically before performing this protocol routinely.</li>
	<li>Perform serial dilutions of homogenized organ suspensions. Plate dilutions on LB agar plates, containing antibiotics when appropriate, and incubate overnight (~15 hr) at 37 &#176;C. UPEC strains have very rapid doubling times and as such, care should be taken to not incubate the agar plates too long because this will hinder the ability to count individual colonies.</li>
</ol>
7. Flow Cytometric Analysis of Bladder Tissue
<ol>
	<li>Prepare digestion buffer containing collagenase at 34 units/mL and DNase at 100 &#181;g/mL, in PBS. Keep on ice. Prepare one 15 ml conical tube per animal to be analyzed and aliquot 1 ml digestion buffer per tube.</li>
	<li>At predetermined timepoints, sacrifice mice using approved standard operating procedures (e.g., cervical dislocation or carbon dioxide overdose). Moisten the abdomen thoroughly with 70% ethanol to minimize contamination by fur.</li>
	<li>Make an incision across the lower third of the mouse&#39;s abdomen of at least 2 cm using scissors and remove the entire bladder. Mince well with scissors, cutting the bladder into 2 - 3 mm2 sized pieces, typically about 8 pieces.
	<ol>
		<li>Add one minced bladder per tube containing digestion buffer. Shake to wash minced bladder tissue into the digestion buffer. Keep on ice until all bladders are dissected and minced.</li>
	</ol>
	</li>
	<li>Incubate minced bladders for 60 - 75 min at 37 &#176;C, with vigorous shaking by hand for 5 s every 15 min. When the tissue has a glassy transparent appearance, resembling wet tissue paper, digestion is complete. Prolonged digestion will remove surface proteins from the cells needed for identification and should be avoided.</li>
	<li>Inactivate the digestion enzymes by adding 2 - 3 mL of ice-cold flow cytometry buffer (PBS containing 2% fetal bovine serum (FBS) and 0.2 mM EDTA) and mix gently. Place tubes on ice.</li>
	<li>To ensure a single cell suspension and to remove any connective tissue, pass the contents of the tube through a 100 &#181;m filter placed in a 15 mL conical tube. Gently press any remaining tissue through the filter with the end of a syringe plunger. Wash the filter with an additional 2 mL flow cytometry buffer. Keep samples on ice.</li>
	<li>Wash samples by centrifugation for 7 min at 200 x g, 4 &#176;C. Resuspend pellets in 100 &#181;L flow cytometry buffer containing Fc block, diluted to 5 &#181;g/mL and transfer to a 96-well round bottom plate. After 10 - 15 min, add 100 &#181;L desired antibody cocktail to each sample. Incubate samples for 30 - 45 min, on ice, protected from light. 
	Note: Fc block is a reagent used to prevent the binding of the Fc portion of antibodies to cells expressing Fc receptors. Its purpose is to minimize nonspecific antibody binding. Determination of antibodies to use will be dependent upon the hypothesis being tested in the experiment and should be selected with input from the literature. In Figure 3, to measure the overall immune cell infiltration, an anti-CD45 antibody was employed, which is a pan-immune cell protein.</li>
	<li>Wash samples by centrifugation for 7 min at 200 x g, 4 &#176;C. Resuspend cell pellets in 200 &#181;L flow cytometry buffer and pass samples through a 40 &#181;m cell strainer on a 5 ml polystyrene tube just prior to acquisition on a flow cytometer.</li>
	<li>Collect the entire sample on the flow cytometer. A good digestion will yield 200,000 - 400,000 cells, with 8,000 - 10,000 CD45+ immune cells from na&#239;ve mouse bladders, while infected organs will contain more cells16 (Figure 3). 
	Note: Samples prepared for flow cytometric analysis cannot be used to evaluate CFU. It is not recommended to split the bladder into two parts as no evidence exists to demonstrate that UPEC colonization or immune cell infiltration is uniform throughout the tissue.</li>
</ol>

<ol><li>Hooton, T. M., Stamm, W. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Diagnosis+and+treatment+of+uncomplicated+urinary+tract+infection%5BTitle%5D)+AND+%22Infect+Dis+Clin+North+Am%22%5BJournal%5D)">Diagnosis and treatment of uncomplicated urinary tract infection.</a> Infect Dis Clin North Am. 11 (3), 551-581 (1997).</li>
<li>Harper, M., Fowlis, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Management+of+urinary+tract+infections+in+men%5BTitle%5D)+AND+%22Trends+in+Urology%2C+Gynaecology+%26+Sexual+Health%22%5BJournal%5D)">Management of urinary tract infections in men.</a> Trends in Urology, Gynaecology & Sexual Health. 12 (1), 30-35 (2007).</li>
<li>Foxman, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+epidemiology+of+urinary+tract+infection%5BTitle%5D)+AND+%22Nat+Rev+Urol%22%5BJournal%5D)">The epidemiology of urinary tract infection.</a> Nat Rev Urol. 7 (12), 653-660 (2010).</li>
<li>Lipsky, B. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Urinary+tract+infections+in+men.+Epidemiology%2C+pathophysiology%2C+diagnosis%2C+and+treatment%5BTitle%5D)+AND+%22Ann+Intern+Med%22%5BJournal%5D)">Urinary tract infections in men. Epidemiology, pathophysiology, diagnosis, and treatment.</a> Ann Intern Med. 110 (2), 138-150 (1989).</li>
<li>Conway, L. J., Carter, E. J., Larson, E. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Risk+Factors+for+Nosocomial+Bacteremia+Secondary+to+Urinary+Catheter-Associated+Bacteriuria%3A+A+Systematic+Review%5BTitle%5D)+AND+%22Urol+Nurs%22%5BJournal%5D)">Risk Factors for Nosocomial Bacteremia Secondary to Urinary Catheter-Associated Bacteriuria: A Systematic Review.</a> Urol Nurs. 35 (4), 191-203 (2015).</li>
<li>Markle, J. G., Fish, E. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((SeXX+matters+in+immunity%5BTitle%5D)+AND+%22Trends+Immunol%22%5BJournal%5D)">SeXX matters in immunity.</a> Trends Immunol. 35 (3), 97-104 (2014).</li>
<li>Yu, C. Y., Whitacre, C. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Sex%2C+MHC+and+complement+C4+in+autoimmune+diseases%5BTitle%5D)+AND+%22Trends+Immunol%22%5BJournal%5D)">Sex, MHC and complement C4 in autoimmune diseases.</a> Trends Immunol. 25 (12), 694-699 (2004).</li>
<li>Castelao, J. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Gender-+and+smoking-related+bladder+cancer+risk%5BTitle%5D)+AND+%22J+Natl+Cancer+Inst%22%5BJournal%5D)">Gender- and smoking-related bladder cancer risk.</a> J Natl Cancer Inst. 93 (7), 538-545 (2001).</li>
<li>Donsky, H., Coyle, S., Scosyrev, E., Messing, E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Sex+differences+in+incidence+and+mortality+of+bladder+and+kidney+cancers%3A+national+estimates+from+49+countries%5BTitle%5D)+AND+%22Urol+Oncol%22%5BJournal%5D)">Sex differences in incidence and mortality of bladder and kidney cancers: national estimates from 49 countries.</a> Urol Oncol. 32 (1), 40-e31 (2014).</li>
<li>Garg, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Gender+Disparities+in+Hematuria+Evaluation+and+Bladder+Cancer+Diagnosis%3A+A+Population-Based+Analysis%5BTitle%5D)+AND+%22J+Urol%22%5BJournal%5D)">Gender Disparities in Hematuria Evaluation and Bladder Cancer Diagnosis: A Population-Based Analysis.</a> J Urol. , (2014).</li>
<li>Dobruch, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Gender+and+Bladder+Cancer%3A+A+Collaborative+Review+of+Etiology%2C+Biology%2C+and+Outcomes%5BTitle%5D)+AND+%22Eur+Urol%22%5BJournal%5D)">Gender and Bladder Cancer: A Collaborative Review of Etiology, Biology, and Outcomes.</a> Eur Urol. , (2015).</li>
<li>Hsu, J. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Decreased+tumorigenesis+and+mortality+from+bladder+cancer+in+mice+lacking+urothelial+androgen+receptor%5BTitle%5D)+AND+%22Am+J+Pathol%22%5BJournal%5D)">Decreased tumorigenesis and mortality from bladder cancer in mice lacking urothelial androgen receptor.</a> Am J Pathol. 182 (5), 1811-1820 (2013).</li>
<li>El Behi, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((An+essential+role+for+decorin+in+bladder+cancer+invasiveness%5BTitle%5D)+AND+%22EMBO+Mol+Med%22%5BJournal%5D)">An essential role for decorin in bladder cancer invasiveness.</a> EMBO Mol Med. 5 (12), 1835-1851 (2013).</li>
<li>Foxman, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Epidemiology+of+urinary+tract+infections%3A+incidence%2C+morbidity%2C+and+economic+costs%5BTitle%5D)+AND+%22Am+J+Med%22%5BJournal%5D)">Epidemiology of urinary tract infections: incidence, morbidity, and economic costs.</a> Am J Med. 113, Suppl 1A. 05S-13S (2002).</li>
<li>Ingersoll, M. A., Kline, K. A., Nielsen, H. V., Hultgren, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((G-CSF+induction+early+in+uropathogenic+Escherichia+coli+infection+of+the+urinary+tract+modulates+host+immunity%5BTitle%5D)+AND+%22Cell+Microbiol%22%5BJournal%5D)">G-CSF induction early in uropathogenic Escherichia coli infection of the urinary tract modulates host immunity.</a> Cell Microbiol. 10 (12), 2568-2578 (2008).</li>
<li>Mora-Bau, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Macrophages+Subvert+Adaptive+Immunity+to+Urinary+Tract+Infection%5BTitle%5D)+AND+%22PLoS+Pathog%22%5BJournal%5D)">Macrophages Subvert Adaptive Immunity to Urinary Tract Infection.</a> PLoS Pathog. 11 (7), e1005044(2015).</li>
<li>Oliveira, P. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Technical+Report%3A+Technique+of+Bladder+Catheterization+in+Female+Mice+and+Rats+for+Intravesical+Instillation+in+Models+of+Bladder+Cancer%5BTitle%5D)+AND+%22%28Conference+Title%2939th+Scand-LAS+and+ICLAS+Joint+Meeting%22%5BJournal%5D)">Technical Report: Technique of Bladder Catheterization in Female Mice and Rats for Intravesical Instillation in Models of Bladder Cancer.</a> (Conference Title)39th Scand-LAS and ICLAS Joint Meeting. 36, 5-9 (2009).</li>
<li>Seager, C. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Intravesical+delivery+of+rapamycin+suppresses+tumorigenesis+in+a+mouse+model+of+progressive+bladder+cancer%5BTitle%5D)+AND+%22Cancer+Prev+Res+%28Phila%29%22%5BJournal%5D)">Intravesical delivery of rapamycin suppresses tumorigenesis in a mouse model of progressive bladder cancer.</a> Cancer Prev Res (Phila). 2 (12), 1008-1014 (2009).</li>
<li>Hagberg, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Ascending%2C+unobstructed+urinary+tract+infection+in+mice+caused+by+pyelonephritogenic+Escherichia+coli+of+human+origin%29%5BTitle%5D)+AND+%22Infect+Immun%22%5BJournal%5D)">Ascending, unobstructed urinary tract infection in mice caused by pyelonephritogenic Escherichia coli of human origin).</a> Infect Immun. 40 (1), 273-283 (1983).</li>
<li>Olson, P. D., Hruska, K. A., Hunstad, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Androgens+Enhance+Male+Urinary+Tract+Infection+Severity+in+a+New+Model%5BTitle%5D)+AND+%22J+Am+Soc+Nephrol%22%5BJournal%5D)">Androgens Enhance Male Urinary Tract Infection Severity in a New Model.</a> J Am Soc Nephrol. , (2015).</li>
<li>Knipper, J. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Interleukin-4+Receptor+alpha+Signaling+in+Myeloid+Cells+Controls+Collagen+Fibril+Assembly+in+Skin+Repair%5BTitle%5D)+AND+%22Immunity%22%5BJournal%5D)">Interleukin-4 Receptor alpha Signaling in Myeloid Cells Controls Collagen Fibril Assembly in Skin Repair.</a> Immunity. 43 (4), 803-816 (2015).</li>
<li>Hung, C. S., Dodson, K. W., Hultgren, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+murine+model+of+urinary+tract+infection%5BTitle%5D)+AND+%22Nat+Protoc%22%5BJournal%5D)">A murine model of urinary tract infection.</a> Nat Protoc. 4 (8), 1230-1243 (2009).</li>
<li>Wright, K. J., Seed, P. C., Hultgren, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Development+of+intracellular+bacterial+communities+of+uropathogenic+Escherichia+coli+depends+on+type+1+pili%5BTitle%5D)+AND+%22Cell+Microbiol%22%5BJournal%5D)">Development of intracellular bacterial communities of uropathogenic Escherichia coli depends on type 1 pili.</a> Cell Microbiol. 9 (9), 2230-2241 (2007).</li>
</ol>

The authors have nothing to disclose.

Transurethral instillation of male mice offers many new research opportunities into the influence of sex on bladder mucosal disease, but also presents several challenges. Foremost, one limitation is that the instillation may initially prove to be technically difficult, resulting in excessive inflammation during catheter insertion. Improvement in technique can be achieved by the instillation of dead mice with a colored solution, such as Evans blue dye. To confirm that the instillation is successful, bladders should be vis...

Urinary tract infections (UTI) are one of the most common infections in developed countries1. Infection rates are similar between females and males among neonates and the elderly2. Premenopausal adult women, however, have a greatly increased incidence of community-acquired UTI compared to men2,3. Given that this disease primarily impacts women, fundamental and clinical research has overwhelmingly focused on UTI in females. However, UTI in men is a significant and understudied health care challenge4. Indeed, because UTI in men are associated with higher morbidity, these infections are routinely defined as complicated4,5.
As our understanding of the central role of sex biases in physiology and pathology evolves, new methods are required to explore this previously neglected aspect of disease. Sex differences play an essential role in immunity and infection; females have higher incidence of autoimmune disease, while males are more susceptible to certain infections, such as tuberculosis, malaria, and HIV6,7. Bladder cancer, another urologic pathology, is significantly more prevalent in men than in women, and several studies have shown a role for androgens in the development of malignancy8,9,10,11,12. Notably, however, investigation of intravesical therapies for bladder cancer is performed exclusively in female animals, due to the inability to repeatedly catheterize male mice13.
The study of UTI pathogenesis relies heavily on rodent models of infection (e.g., mice and rats). Murine models of UTI may employ uropathogens originally isolated from human infections, such as uropathogenic E. coli (UPEC), Klebsiella, Enterococcus, Staphylococcus, or Proteus14. Typically, bacteria are introduced into the bladder via catheterization of the urethra. Following infection, bladders and kidneys can be removed to assess specific parameters of infection, such as bacterial colonization, tissue damage, or host immune response15,16. Universally, however, only female animals are used for UTI research. Indeed, many studies have noted that, due to anatomical reasons, catheterization of male mice is not possible13,17,18,19. More recently, a surgical approach to male instillation has been described, in which the abdomen is opened, the bladder is externally displaced by applying gentle pressure to the opening in the abdomen, and bacteria are injected into the bladder20. This approach enables male infection, at the cost of surgical intervention. Thus, a major caveat of this approach includes the influence of inflammation, on the outcome of infection such as the potential to induce an anti-inflammatory wound-healing response to the incision21. As our interests include understanding sex bias in response to disease, we developed a method of bacterial intravesical instillation in male mice that more closely matches the long-established non-surgical transurethral approach used in female rodents22.
Our model builds upon an established methodology and provides the ability to directly compare the host immune response to UTI in female and male animals. This method will permit dissection of sex-based differences in infection, and potentially offer molecular and cellular clues to the pronounced differences in susceptibility and response to infection between the sexes. Additionally, this model has value beyond UTI studies, allowing the establishment of models to investigate other bladder-associated diseases, such as bladder cancer, prostatitis, under- or over-active bladder syndrome, and interstitial cystitis.

<table><tbody><tr><td>BD Insyte Autoguard Shielded IV Catheters 24 G, 0.7 mm external diameter, 14 mM long</td><td>BD Medical</td><td>381811 or 381411*</td><td>* catalog number is country-dependent</td></tr><tr><td>inoculating loop</td><td>Greiner Bio-One</td><td>731171</td><td></td></tr><tr><td>LB Miller broth</td><td>Difco</td><td>244620</td><td></td></tr><tr><td>LB Miller agar</td><td>Difco</td><td>244520</td><td></td></tr><tr><td>Cuvettes</td><td>Bio-rad</td><td>223-9955</td><td></td></tr><tr><td>syringes</td><td>B Braun</td><td>9166017V</td><td></td></tr><tr><td>Thumb (Adson) forceps</td><td>Fine Science Tools</td><td>11006-12</td><td></td></tr><tr><td>5 ml tubes, polypropylene</td><td>Falcon</td><td>352063</td><td></td></tr><tr><td>Tissue Ruptor disposable probes</td><td>Qiagen</td><td>990890</td><td></td></tr><tr><td>15 ml flip cap tubes</td><td>Thermo Scientific</td><td>362694</td><td></td></tr><tr><td>DNAse</td><td>Invitrogen</td><td>18047019</td><td></td></tr><tr><td>Liberase TM</td><td>Sigma-Aldrich</td><td>5401119001</td><td>should be aliquotted and stored at -20 &amp;deg;C to avoid repeated freeze-thaw</td></tr><tr><td>100 &amp;micro;M MACS SmartStrainers&amp;nbsp;</td><td>Miltenyi</td><td>130-098-463</td><td>compatible with 15 ml tubes, preferred</td></tr><tr><td>100 &amp;micro;m cell strainers&amp;nbsp;</td><td>Falcon</td><td>352360</td><td>compatible with 50 ml tubes, if MACS Smart Strainers are not available</td></tr><tr><td>96 well plate</td><td>Falcon</td><td>353077</td><td></td></tr><tr><td>Fc block</td><td>BD Pharmingen</td><td>553142</td><td>anti-CD16/CD32</td></tr><tr><td>anti-mouse CD45 antibody</td><td>BD Biosciences</td><td>561487</td><td>many different fluorescent conjugation options are available</td></tr><tr><td>5 ml tubes polystyrene with filter cap</td><td>Falcon</td><td>352235</td><td></td></tr><tr><td>insulin syringe</td><td>Terumo</td><td>BS05M2913</td><td></td></tr><tr><td>hand held homogenizer</td><td>Qiagen</td><td>9001272</td><td>TissueRuptor</td></tr><tr><td>flow cytometer</td><td>BD Biosciences</td><td>N/A</td><td>Fortessa SORP&amp;nbsp;</td></tr><tr><td>Flow cytometry software</td><td>BD Biosciences</td><td>N/A</td><td>Diva</td></tr></tbody></table>

urinary tract infection in a small animal model: transurethral catheterization of male and female mice

Urinary Tract Infection in a Small Animal Model: Transurethral Catheterization of Male and Female Mice

Urinary tract infections (UTI) are extremely common worldwide, incurring significant morbidity and healthcare-associated expenses. Small animal models, which accurately reflect disease establishment and progression, permit dissection of host-pathogen interactions and generation of immunity to infection. In mice, intravesical instillation of uropathogenic E. coli, the causative agent in more than 85% of community acquired UTI, recapitulates many of the stages of infection observed in humans. Until recently, however, UTI could only be modeled in female animals. This limitation has hindered the study of sex-related differences in UTI, as well as other bladder pathologies, such as cancer. Here, we describe a method to instill male mice that allows direct comparison between female and male animals and provide a detailed protocol to assess bladder tissue by flow cytometry as a means to better understand host responses to infection. Together, these approaches will aid in the identification of host factors that contribute to sex biases observed in UTI and other bladder-associated diseases.

In the development of this protocol, cohorts of female and male C57Bl/6 mice aged 6 to 8 weeks were instilled, and bacterial burden evaluated in bladders at time points ranging from 1 hr to 30 days. The results from these studies are detailed elsewhere (Zychlinsky Scharff et al., pending). Here, we present representative data from 24 hr infections. Notably, bacterial burden was equivalent between male and female mice at 24 hr post-infection (Figure 1). Little var...

The established model of transurethral catheterization of mice allows the study of bladder pathologies, including urinary tract infection, but can only be performed in females. A new model of male transurethral instillation, presented here, will enable research in an area marked by strong clinical and epidemiological differences between the sexes.

Urinary tract infections (UTI) are extremely common worldwide, incurring significant morbidity and healthcare-associated expenses. Small animal models, ...

urinary-tract-infection-small-animal-model-transurethral

Research

JoVE Journal

Immunology and Infection

This video will demonstrate methods to transurethrally induce mouse urinary tract infections and quantify the extent of resulting infections.

Transurethral Induction of Mouse Urinary Tract Infection

Source: Luyts, N., et al. Longitudinal Follow-Up of Urinary Tract Infections and Their Treatment in Mice using Bioluminescence Imaging. J. Vis. Exp. (2021).This video demonstrates the induction and tracking of urinary tract infection in a mouse model using bioluminescent E. coli injected into the bladder, where bacterial adhesion, invasion, and intracellular replication occur. The emitted light from the bioluminescent operon serves as a real-time marker of bacterial load during infection...

Visualization of Urinary Tract Infection in a Mouse Model Using Bioluminescence

Source: Conover, M. S., et al., J. Establishment and Characterization of UTI and CAUTI in a Mouse Model. J. Vis. Exp. (2015)This video demonstrates the procedure for assembling and implanting a transurethral catheter in a female mouse, followed by bacterial inoculation to establish catheter-associated urinary tract infection and investigate biofilm-mediated host-pathogen interactions.

Catheter-Associated Urinary Tract Infection in a Mouse Model

In this video, we describe the technique for the intravesical administration of uropathogenic bacteria to generate a urinary tract infection model in mice. This model can be used to understand the spread of uropathogenic bacterial infection within the urinary system and the mechanisms that determine UTI susceptibility.

Generating Urinary Tract Infection Model: A Technique to Administer Uropathogenic Bacteria in Mouse to Develop Urinary Tract Infection Model

This video demonstrates the establishment of uropathogenic Escherichia coli infection in a female mouse bladder through transurethral catheter instillation. The injected bacteria successfully establish a urinary tract infection within the bladder, providing a valuable platform for studying healthcare-associated diseases related to the urinary tract.

Transurethral Catheterization and Bacterial Inoculation to Generate a Urinary Tract Infection Model in Male Mice

Establishment of a Urinary Tract Infection Model in Female Mice

This video demonstrates a technique to assess the anti-tumor activity of Helicobacter pylori neutrophil-activating protein, or HP-NAP, in a mouse bladder cancer model. HP-NAP interacts with tumor-cell neutrophils to produce pro-inflammatory cytokines, inducing the differentiation of naïve T cells into type 1 T helper (Th1) and type 1 cytotoxic (Tc1) T cell phenotypes. The Th1 and Tc1 cells secrete interferon-gamma, inhibiting tumor angiogenesis and promoting cytotoxic T cell-mediated tumor...

Evaluating the Anti-Tumor Efficacy of a Bacterial Immunomodulatory Protein in a Murine Model

The ability to model urinary tract infections (UTI) is crucial in order to be able to understand bacterial pathogenesis and spawn the development of novel therapeutics. This work’s goal is to demonstrate mouse models of experimental UTI and catheter associated UTI that recapitulate and predict findings seen in humans.

Establishment and Characterization of UTI and CAUTI in a Mouse Model

Transurethral instillation is a challenging procedure and has not been well described in the literature. The aim of this manuscript is to describe a technique for transurethral insertion of a catheter for intravesical delivery of liquids with active substances into the urinary bladder and/or prostate in adult male mice.

Transurethral Instillation Procedure in Adult Male Mouse

A mouse model of uropathogenic E. coli (UPEC) transurethral inoculation to establish latent intracellular bladder reservoirs and subsequent bladder exposure to G. vaginalis to induce recurrent UPEC UTI is demonstrated. Also demonstrated are the enumeration of bacteria, urine cytology, and in situ bladder fixation and processing for scanning electron microscopy.

Recurrent Escherichia coli Urinary Tract Infection Triggered by Gardnerella vaginalis Bladder Exposure in Mice

This manuscript describes the intravesical administration of uropathogenic bacteria with a lux operon to induce a urinary tract infection in mice and subsequent longitudinal in vivo analysis of the bacterial load using bioluminescence imaging.

Longitudinal Follow-Up of Urinary Tract Infections and Their Treatment in Mice using Bioluminescence Imaging

Learn transurethral catheterization for urinary tract infection research using male and female mice. This method enables comparative study of sex-based immune responses in bladder pathologies.

Urinary Tract Infection in a Small Animal Model: Transurethral Catheterization of Male and Female Mice

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