Ultrasonography of the Adult Male Urinary Tract for Urinary Functional Testing

Summary

We describe the use of high frequency ultrasound with contrast imaging as a method to measure bladder volume, bladder wall thickness, urine velocity, void volume, void duration, and urethral diameter. This strategy can be used to assess voiding dysfunction and treatment efficacy in various mouse models of lower urinary tract dysfunction (LUTD).

Abstract

The incidence of clinical benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS) is increasing due to the aging population, resulting in a significant economic and quality of life burden. Transgenic and other mouse models have been developed to recreate various aspects of this multifactorial disease; however, methods to accurately quantitate urinary dysfunction and the effectiveness of new therapeutic options are lacking. Here, we describe a method that can be used to measure bladder volume and detrusor wall thickness, urinary velocity, void volume and void duration, and urethral diameter. This would allow for the evaluation of disease progression and treatment efficacy over time. Mice were anesthetized with isoflurane, and the bladder was visualized by ultrasound. For non-contrast imaging, a 3D image was taken of the bladder to calculate volume and evaluate shape; the bladder wall thickness was measured from this image. For contrast-enhanced imaging, a catheter was placed through the dome of the bladder using a 27-gauge needle connected to a syringe by PE50 tubing. A bolus of 0.5 mL of contrast was infused into the bladder until a urination event occurred. Urethral diameter was determined at the point of the Doppler velocity sample window during the first voiding event. Velocity was measured for each subsequent event yielding a flow rate. In conclusion, high frequency ultrasound proved to be an effective method for assessing bladder and urethral measurements during urinary function in mice. This technique may be useful in the assessment of novel therapies for BPH/LUTS in an experimental setting.

Introduction

Benign prostatic hyperplasia (BPH) is a disease that develops in men as they age and affects nearly 90% of men over 80 years of age^1,2. Although the development of BPH is generally associated with aging, other factors including obesity and metabolic syndrome can lead to BPH in relatively younger men^3,4. Many men with BPH develop lower urinary tract symptoms (LUTS) that significantly decrease their quality of life, and some experience complications that may include bleeding, infection, bladder outlet obstruction (BOO), bladder stones, and renal failure.....

Protocol

Procedures involving animal subjects have been approved by the Institutional Animal Care and Use Committee (IACUC) at the University of Wisconsin – Madison.

1. Animal preparation

1. Place a 24-month-old, C57Bl6/J male mouse in a pre-charged chamber with 3-5% isoflurane until the righting reflex is lost and the breathing rate slows.
2. If necessary, use clippers to shave the abdominal hair from the animal for surgery and/or imaging. Remove all remaining hair using a depila.......

Discussion

Current techniques for evaluating the lower urinary tract of rodents are limited by their ability to directly correlate changes in voiding physiology with changes in prostatic histology consequent to disease progression. Void spot assays and uroflowmetry can be used to assess spontaneous urination events in rodents, and these techniques can be used to evaluate changes over a period of time^15,16,17. However, for both techniques, .......

Materials

Name	Company	Catalog Number	Comments
21mm Clear Tubing	Supera Anesthesia Innov	301-150
27 gauge needle	BD	Z192376
4 port Manifold	Supera Anesthesia Innov	RES536
DEFINITY	Lantheus Medical Imaging	DE4
F/AIR Canister	Supera Anesthesia Innov	80120
Graefe forceps (Serrated, Straight)	F.S.T.	11050-10
Inlet/Outlet Fittings	Supera Anesthesia Innov	VAP203/4
Isoflurane	Midwest Vet Supply	193.33161.3
Isoflurane Vaporizer	Supera Anesthesia Innov	VAP3000
MV707 probe	Fujifilm VisualSonics Inc
Oxygen Flowmeter	Supera Anesthesia Innov	OXY660
Polyethylene 50 tubing	BD	427516
Pressure Reg/Gauge	Supera Anesthesia Innov	OXY508
Rebreathing Circuits	Supera Anesthesia Innov	CIR529
Small Mice Nose Cone	Supera Anesthesia Inov	ACC526
Sterile saline	Midwest Vet Supply	193.74504.3	NaCl 0.9%, Injectable
Straight Sharp/Blunt Scissors	Fine Scientific Tools (F.S.T)	14054-13
Syringe	BD	309646	5mL
Vevo 770	Fujifilm VisualSonics Inc
VIALMIX	Lantheus Medical Imaging	VMIX