Transurethral Instillation Procedure in Adult Male Mouse

Summary

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.

Abstract

Transurethral instillation can be used to deliver different solutions with active ingredients (e.g., drugs, chemicals, bacteria, and viruses) locally into the urinary bladder to either induce animal models of bladder pathologies or evaluate the effectiveness of intravesical treatments. Most rodent models of lower urinary tract (LUT) pathologies are induced in female mice due to ease of intravesical instillation of the substances via the female urethra. However, due to anatomical differences between the female and male LUT, transurethral instillation in a male mouse has been deemed a very challenging procedure, and it has not been previously described. In this manuscript, we provide a detailed description of how to prepare polyethylene (PE) tubing for subsequent insertion into the urethra of a male mouse. In addition, we discuss the ideal types of PE tubing to be used depending on the desired site of inoculation. Furthermore, we describe point by point how to prepare an animal for a successful transurethral instillation to avoid injury to the urethra and ensure the delivery of the solution to the desired location. The procedure is started by retracting the prepuce and the glans to expose the opening of the urethral meatus. Next, the glans are grasped by blunt non-crushing forceps to stabilize the penis and the PE tubing. The PE tubing is first inserted into the urethral meatus parallel to the animal body, then its angle is adjusted by tilting the catheter to maneuver it to follow the natural curvature of the urethra. This technique can be used to induced murine models of bladder pathologies and/or evaluate the effectiveness of intravesical treatments in male mice.

Introduction

The transurethral instillation approach has been used in previous studies as one of the methods to create rodent models of bladder pathologies^1,2,3,4 and can be used to evaluate the effectiveness of locally delivered treatments in mice. Although animal models cannot fully recapitulate human pathologies, identification of the underlying mechanisms in animal studies provides a better understanding of the human LUT disorders such as interstitial cystitis/bladder pain syndrome, neurogenic cystitis, autoimmune cystitis, and prostatic inflammation....

Protocol

All the procedures with animals, including the method and duration of anesthesia, as well as postoperative care, were discussed with a veterinarian and approved by the Institutional Animal Care and Use Committee (IACUC) at the affiliated institution. In this manuscript, all procedures were performed with 8 to 15-week-old C57BL/6 male mice and the protocol follows the animal care guidelines approved by the IACUC at the University of Colorado.

1. Preparation of Tubing

NOTE: To instill the inoculum, a needle attached to the polyethylene (PE) tubing (Figure 1A) or a small gauge (<24 G)....

Results

Transurethral instillation of blue dye via PE 50 tubing resulted in instillation of the dye into the urinary bladder (Figure 4A), and via PE 10 tubing in colorization of the SV and AP (Figure 4B), respectively. To evaluate whether the performed transurethral instillation causes an instant reflux of the inoculum to the kidneys or not, the kidney and ureter were observed followed by instillation of 100 µL of the blue dye and fluore.......

Discussion

This manuscript describes in detail a method of transurethral instillation in adult male mouse. Differential primary seeding area can be reached by using PE tubing of different diameters. PE-50 is recommended for successfully reaching the urinary bladder lumen, while a larger diameter PE-10 is used to reach the AP and SV (Figure 3A-B). In addition to the choice of size of PE tubing and target organ for inoculation, other factors, such as the volume of instilled inoculum, als.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
BD INTRAMEDIC Polyethylene Tubing/ PE 10	BD Medical	63019-004
BD INTRAMEDIC Polyethylene Tubing/ PE 50	BD Medical	63019-048
BD Insyte-N Autoguard/ Angiocath	BD Medical	311411
Ethanol (EtOH)	Fisher Scientific	BP2818500
BD Needle Only 22 Gauge (G) 1 inch	Becton Dickson	205155
BD Needle Only 27 Gauge (G) 1/2 inch	Becton Dickson	305129
Luer stub, 22 G X 0.5 in / Blunt Needle	Instech	LS22
Luer stub, 27 G X 0.5 in / Blunt Needle	Instech	LS27
6" Long x 2" Wide x 1" Thick, Aluminum Oxide Sharpening Stone / Oil Stone	Norton	40204034
Surgical Lubricant Sterile Bacteriostatic Folilpac	Surgilube	281020543
Isoflurane	Fluriso	13985-528-60
SomnoSuite Low-Flow Anesthesia System	Kent Scientific	SS-01
Dissecting Forceps, Curved	vwr	82027-392
BD 1 ml Syringe	BD Medical	309626
India Ink Solution., 0.2% in PBS buffer	Alfa Aesar	J61007
8~12 weeks old male C57B/6 Mice	Jackson Lab	#000664