An animal model induced by bilateral cavernous nerve crushing mimics post-radical prostatectomy erectile dysfunction in old rats

Abstract

Aim: Over the years, the cavernous nerve (CN) crushing injury rat model has been frequently used for studying post-radical prostatectomy erectile dysfunction (pRP-ED). However, models based on young and healthy rats reportedly exhibit spontaneous recovery of erectile function. Our investigation purpose was to evaluate bilateral CN crushing (BCNC) effects on erectile function besides penile corpus cavernosum pathology in young and old rats and verify whether the BCNC modeling in old rats is more suitable to mimic pRP-ED.

Materials and methods: Thirty young and old male Sprague-Dawley (SD) rats had been divided into three groups in a random manner: sham-operated group (Sham), CN-injured 2-week group (BCNC-2W), and CN-injured 8-week group (BCNC-8W). At 2 and 8 weeks postoperatively, mean arterial pressure (MAP) along with intracavernosal pressure (ICP) had been determined, respectively. Then, the penis was harvested for histopathological studies.

Key finding: We found that young rats exhibited erectile function spontaneous recovery 8 weeks following BCNC, while old ones failed to recover erectile function. After BCNC, the abundance of nNOS-positive nerve and smooth muscle were reduced, whereas apoptotic levels and collagen I content increased. These pathological modifications gradually resumed over time in young rats, unlike in old rats.

Significance: Our findings demonstrate that 18-month-old rats do not spontaneously regain erectile function at 8 weeks after BCNC. Therefore, CN-injury ED modeling in 18-month-old rats may be more suitable for studying pRP-ED.

Keywords: Animal model; Cavernous nerve injury; Erectile dysfunction; Intracavernosal pressure.