A novel method to establish a rat ED model using internal iliac artery ligation combined with hyperlipidemia

Anatomical variations of the arterial branches from the rat iliac arteries

Animal disease models contribute to a better understanding of the pathogenic mechanisms of human and animal diseases and help develop treatments for them. Ligation of the rat iliac arteries is performed to reproduce erectile dysfunction and peripheral arterial disease. Although knowledge of the ramification of branches from the rat iliac artery is important to perform such surgery, descriptions in previous studies are insufficient. Therefore, 17 male and 18 female Wistar rats were observed to elucidate the detailed ramification patterns of branches from the iliac arteries with the latex injection method. The iliac arteries branched off the umbilical, cranial gluteal, lateral and medial circumflex femoral, external pudendal, and caudal epigastric arteries, and the common trunk of the caudal gluteal and internal pudendal arteries. The branching pattern of the umbilical, cranial and caudal gluteal, and internal pudendal arteries varied greatly and was categorized as Types 1 to 3 based on the number of branching levels along the proximodistal axis of the iliac arteries. Based on the same criteria, the ramification patterns of the lateral and medial circumflex femoral arteries were also divided into Groups 1 and 2. The external pudendal and caudal epigastric arteries originated from the external iliac artery mainly as a common trunk or less frequently as independent arteries in this order. The detailed branching patterns of the rat iliac arteries elucidated in the present study are beneficial for the refinement of surgical procedures.

Comparison of two cannulation methods for assessment of intracavernosal pressure in a rat model

Intracavernous pressure (ICP) measurement is a well-established technique for assessing the erectile function, which was performed by cannulating either crus or shaft of the penis. However, there are no studies concerning the experimental performance of the two cannulation sites yet. The aim of this study was to compare the measuring outcomes using two different cannulation sites. To validate the capacity of our study, both normal and the castration-induced erectile dysfunction rat models were conducted. Fifty adult male Sprague-Dawley rats were randomized equally into two groups: an intact group and a castration group. Five rats from each group firstly underwent different stimulation parameters to detect the optimal erectile responses. The residual rats in each group were further assigned into two subgroups (n = 10 per subgroup) according to two different cannulation sites (crus or shaft of the corpus cavernosum). The ICP values were compared between groups after different interventions. The optimal parameters for mean maximum ICP were recorded at 2.5V and a frequency of 15 Hz. The rats under the two different cannulation sites tended to show similar ICP values in both the intact and the castration groups. However, the success rate in monitoring ICP was significantly higher in the groups cannulating into the shaft of the penis compared to the crus (100% vs. 70%; P = 0.02). Our data suggested that the method of cannulation into the penile shaft could serve as a better alternative for the ICP measurement in rats.

Penile erectile dysfunction after brachial plexus root avulsion injury in rats

Our previous studies have demonstrated that some male patients suffering from brachial plexus injury, particularly brachial plexus root avulsion, show erectile dysfunction to varying degrees. However, the underlying mechanism remains poorly understood. In this study, we evaluated the erectile function after establishing brachial plexus root avulsion models with or without spinal cord injury in rats. After these models were established, we administered apomorphine (via a subcutaneous injection in the neck) to observe changes in erectile function. Rats subjected to simple brachial plexus root avulsion or those subjected to brachial plexus root avulsion combined with spinal cord injury had significantly fewer erections than those subjected to the sham operation. Expression of neuronal nitric oxide synthase did not change in brachial plexus root avulsion rats. However, neuronal nitric oxide synthase expression was significantly decreased in brachial plexus root avulsion + spinal cord injury rats. These findings suggest that a decrease in neuronal nitric oxide synthase expression in the penis may play a role in erectile dysfunction caused by the combination of brachial plexus root avulsion and spinal cord injury.