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

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
<ol>
	<li>Prepare the f...

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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...

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.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>25 G needle</td>
			<td>BD Bioscience</td>
			<td>367391</td>
			<td></td>
		</tr>
		<tr>
			<td>Abdominal retractor</td>
			<td>RWD Life Science</td>
			<td>R22009-01</td>
			<td></td>
		</tr>
		<tr>
			<td>Animal operating pad</td>
			<td>Provided by Guangdong Provincial Key Laboratory of Biomedical Imaging</td>
			<td>NA</td>
			<td></td>
		</tr>
		<tr>
			<td>Bending forceps</td>
			<td>RWD Life Science</td>
			<td>F12011-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Biological signal acquisition and processing system</td>
			<td>Techman Software</td>
			<td>BL-420S</td>
			<td></td>
		</tr>
		<tr>
			<td>Bipolar electrode</td>
			<td>Techman Software</td>
			<td>AC0047</td>
			<td></td>
		</tr>
		<tr>
			<td>Carprofen</td>
			<td>Sigma-Aldrich</td>
			<td>MFCD00079028</td>
			<td></td>
		</tr>
		<tr>
			<td>HARTMAN mosquito hemostatic forceps</td>
			<td>RWD Life Science</td>
			<td>F22002-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Heparin</td>
			<td>Shanghai Aladdin Biochemical Technology</td>
			<td>2608411</td>
			<td></td>
		</tr>
		<tr>
			<td>Micro needle holder</td>
			<td>RWD Life Science</td>
			<td>F31047-12</td>
			<td></td>
		</tr>
		<tr>
			<td>Microsurgery forceps</td>
			<td>RWD Life Science</td>
			<td>F11001-11</td>
			<td></td>
		</tr>
		<tr>
			<td>Scalpel</td>
			<td>RWD Life Science</td>
			<td>S32003-12</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium pentobarbital</td>
			<td>Guangdong Provincial Key Laboratory of Biomedical Imaging</td>
			<td>NA</td>
			<td></td>
		</tr>
		<tr>
			<td>Sprague&#8211;Dawley rat</td>
			<td>Guangdong Medical Laboratory Animal Center</td>
			<td>GDMLAC-035</td>
			<td></td>
		</tr>
		<tr>
			<td>Thread scissors</td>
			<td>RWD Life Science</td>
			<td>S15001-11</td>
			<td></td>
		</tr>
		<tr>
			<td>Tissue forceps</td>
			<td>RWD Life Science</td>
			<td>F13019-12</td>
			<td></td>
		</tr>
		<tr>
			<td>Tissue scissors</td>
			<td>RWD Life Science</td>
			<td>S13029-14</td>
			<td></td>
		</tr>
	</tbody>
</table>

intracavernous pressure recording in a cavernous nerve injury rat model

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.

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...

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Intracavernous Pressure Recording in a Cavernous Nerve Injury Rat Model

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