Intracavernous Pressure Recording in a Cavernous Nerve Injury Rat Model

Published: September 20, 2021

doi:

Zitaiyu Li*^1,2, Yinghao Yin*³, Kancheng He², Kun Ye², Jun Zhou, Hao Qi², Yihong Zhou², Yingbo Dai², Yuxin Tang²

¹Department of Urology,The Fifth Affiliated Hospital of Sun Yat-sen University, ²Guangdong Provincial Key Laboratory of Biomedical Imaging,The Fifth Affiliated Hospital, Sun Yat-sen University, ³Department of Urology,The Third Xiangya Hospital of Central South University

Summary

This protocol describes developing a stable bilateral cavernous nerve injury rat model of radical prostatectomy associated with erectile dysfunction and intracavernous pressure measurement.

Abstract

The bilateral cavernous nerve (CN) injury rat model has been extensively used to simulate clinical cavernous nerve injury associated with erectile dysfunction (ED) for evaluating the effect of clinical therapeutic methods. However, the methods of CN injury model construction are flawed and varied in the ED research field. It is CN crush injury that is the most commonly used method in recent years. This study aims to provide a detailed description of the procedure of bilateral CN injury rat model construction and measurement of intracavernous pressure (ICP) recording, providing a reliable and reproducible CN injury rat model. This work successfully developed the CN injury method of hemostat crush injury using a syringe needle as hard support and a hemostat with a rubber sleeve. Also, this method concludes that a voltage of 1.0 V, frequency of 20 Hz, and pulse-width of 5 ms are the optimized stimulation parameters for ICP recording in a bilateral CN injury rat model.

Introduction

ED is one of the common diseases in adult men. It is estimated that the number of ED patients in the world will reach 322 million by 2025¹. One multicenter extensive sample survey in China shows that the proportion of ED caused by pelvic surgery or trauma is about 8%². Despite the continuous improvement of surgical techniques and surgical instruments, the incidence of ED is still high. It has been considered that the development and progression of ED after nerve-sparing radical prostatectomy (RP) contributes to cavernous nerve injury resulting in atrophy of corpus cavernosum smooth muscle, apoptosis of endothelial cells, and pathological remodeling³^,⁴.

For studying the mechanism of hemodynamics and histopathology changes of CN injury associated with ED, several different types of CN injury animal models have been developed and assessed, including rodent, dog, cat, and monkey⁵^,⁶^,⁷. Relying on the advantages in expenditure and reproducibility, the bilateral CN injury rat model has become the most common model for assessing ED after radical pelvic surgery⁸. However, various forms of nerve injury have been reported in numerous literature whose principal differences are nerve injury approaches (crush, freezing, transection, and excision)⁹^,¹⁰^,¹¹. Furthermore, the diversity of nerve injury approaches might lead to inconsistency in intracavernous pressure (ICP) recording parameters in the rat model, which determines the accuracy and evaluation of ICP⁸. Nevertheless, there is not a standardized method for inducing nerve injury and recording ICP of the model yet.

Therefore, this study aims to build a more reliable and reproducible bilateral CN injury rat model. This method provides a detailed description of the procedure of model construction and ICP measurement, which might be beneficial to study the mechanisms of ED and develop effective treatments in the future.

Protocol

Fifteen adult male Sprague-Dawley rats (3-month-old) weighing between 300-350 g were used in this study. All animal procedures were performed following the NIH Guidelines for the Care and Use of Laboratory Animals and with the approval of The fifth affiliated hospital of Sun Yat-Sen University Institutional Animal Care and Use Committee. Animals were housed in a comfortable facility with temperature and light controlled. 1. Preparation for surgical procedure materials Prepare the f…

Representative Results

The surgery procedure produced a typical ICP response curve using this protocol with the recommended stimulation settings. The ICP response curve rises instantly when stimulating the nerve and drops when the stimulation is withdrawn (Figure 5). It is essential to examine the intracavernous pressure line before measuring the ICP, which affects the evaluation of increased ICP values (Figure 4). As illustrated in Fig…

Discussion

ED is a severe complication of pelvic surgery or trauma. Although undergoing a nerve-sparing operation, the incidence rate of ED is approximately 14-90% in radical prostatectomy (RP)¹². Due to the problematic regeneration of injury CN, the clinical curative effect is less than satisfactory. Thus, a stable CN injury animal model for exploring treatments of ED is essential. Quinlan et al. first reported the CN injury rat model for the study of RP-associated ED¹³. Several stud…

Divulgazioni

The authors have nothing to disclose.

Acknowledgements

This work was supported by the National Natural Science Foundation of China (Grant NO. 82071636).

Materials

25 G needle	BD Bioscience	367391
Abdominal retractor	RWD Life Science	R22009-01
Animal operating pad	Provided by Guangdong Provincial Key Laboratory of Biomedical Imaging	NA
Bending forceps	RWD Life Science	F12011-10
Biological signal acquisition and processing system	Techman Software	BL-420S
Bipolar electrode	Techman Software	AC0047
Carprofen	Sigma-Aldrich	MFCD00079028
HARTMAN mosquito hemostatic forceps	RWD Life Science	F22002-10
Heparin	Shanghai Aladdin Biochemical Technology	2608411
Micro needle holder	RWD Life Science	F31047-12
Microsurgery forceps	RWD Life Science	F11001-11
Scalpel	RWD Life Science	S32003-12
Sodium pentobarbital	Guangdong Provincial Key Laboratory of Biomedical Imaging	NA
Sprague–Dawley rat	Guangdong Medical Laboratory Animal Center	GDMLAC-035
Thread scissors	RWD Life Science	S15001-11
Tissue forceps	RWD Life Science	F13019-12
Tissue scissors	RWD Life Science	S13029-14

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