Detrusor Underactivity Model in Rats by Conus Medullaris Transection

Summary

We present a method for establishing a detrusor underactivity model by conus medullaris transection in rats. Detrusor underactivity was successfully stimulated in these animals. The model can be used for studying urinary tract function.

Abstract

The goal of the presented protocol was to establish a detrusor underactivity (DU) model in the rat through conus medullaris transection. Laminectomy was performed in a total of 40 female Wistar rats (control group: 10 rats; test group: 30 rats) weighing 200–220 g, and the conus medullaris was transected at the L4‒L5 level in the test group. All the rats were housed and fed under the same environmental conditions for six weeks. In the test group, urine voiding was performed twice daily for six weeks, and mean residual urine volume was recorded. A cystometrogram was performed in both groups. Maximum cystometric capacity (MCC), detrusor opening pressure (DOP), and compliance of the bladder were recorded and calculated. The test group showed significant urinary retention after the surgery, both during and after the spinal shock. However, no abnormality was observed in the control group. When compared to the control group, the MCC and compliance of bladder in the test group was significantly higher than that of the test group (3.24 ± 2.261 mL versus 1.04 ± 0.571 mL; 0.43 ± 0.578 mL/cmH₂O versus 0.032 ± 0.016 mL/cmH₂O), whereas DOP in the test group was lower than control (20.28 ± 14.022 cmH₂O versus 35 ± 13.258 cmH₂O). This method of establishing an animal model of DU by the conus medullaris transection offers an excellent opportunity to understand DU’s pathophysiology in a better manner.

Introduction

Detrusor underactivity (DU) is a typical lower urinary tract dysfunction that has remained under studied. Even though DU has been defined by the International Continence Society (ICS)¹, numerous different terminologies are used to refer to this disease, e.g., “detrusor failure,” “acontractile bladder,” “detrusor areflexia”². DU, as defined by the International Continence Society (ICS) in 2002, is a contraction of reduced strength and duration, which results in prolonged increase in time for bladder emptying, thereby resulting in failure to achieve complete bladder emptying within a nor....

Protocol

All rats were used according to protocols approved by the Animal Experimental Committee of Beijing Friendship Hospital, Capital Medical University.

1. Surgical preparation, anesthetization, and surgical techniques

NOTE: A total of 40 female Wistar rats, weighing 200–220 g, were commercially obtained for the present study. Of the 40 rats, 10 were randomly selected as the control group, and the rest were treated as the test group. All animals were housed in a sterile environment in the animal facilities of Beijing Friendship Hospital, Capital Medical University.

1. Perform general anesthesia by admin....

Results

The entire procedure of the conus medullaris transection can be completed within 45 min by experienced surgeons. Our laboratory has performed over 100 cases of conus medullaris transection surgeries. The success rate is over 95%, as defined by the rats’ survival and successful induction of DU. The urodynamic test confirmed the induction of DU.

Based on our experience, the induction of DU can be preliminarily evaluated by the residual urine volume. The retention of urine was observed immediatel.......

Discussion

DU is a common cause of lower urinary tract symptoms in both men and women. It is a complex constellation of symptoms with few treatment options that can significantly diminish the quality-of-life (Qol) of those affected¹⁸. Although it is believed that DU is multifactorial, the understanding of its pathogenesis remains rudimentary. Studies have shown that the pathogenesis of DU might be related to myogenic and neurogenic factors.

In the myogenic hypotheses, it was obser.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
0.9% saline	Wuhan Prosai Company	EY-C1178	pump for urodynamic measurement
10% chloral hydrate	Shandong Yulong Co., Ltd	H37022673	3mL/kg, administered intraperitoneally
Buprenorphine Hydrochloride Injection	Tianjin Pharmaceutical Research Institute Pharmaceutical Co. LTD	H12020275	0.05mg/kg subcutaneously 24h and 48h postoperation
Epidural Catheter	Shandong Xinghua Co, Ltd	VABR3L	for urodynamic measurement
Penicillin G	Alta Technology Co., Ltd	1ST5637	50,000 unit/ml per animal
pentobarbital	Beijing solabo Technology Co., Ltd	NK-WF0001	40 mg/kg, administered intraperitoneally
Suture line(4-0)	ETHICON	VCP422H	suture the injury
Three-limb tube	Shandong Xinghua Co, Ltd	VAB3T	for urodynamic measurement
Trace infusion pump	Zhejiang Smith Medical Instrument Co., Ltd	20162540335	Pump the saline at a speed of 0.2ml/min for urodynamic measurement
Urodynamic measurement equipment	Medical Measurement SystemsB.V.	08-0467	urodynamic measurement equipment can not only help the diagnosis of dysuria, but also provide objective materials for treatment and therapeutic effect. It is the most commonly used examination method in clinical diagnosis and treatment of lower urinary tract functional diseases
Wistar Rats	HFK Biotechnology Co.Ltd,Beijing ,China	SCXK2012-0023	200-220g