Electrocautery-induced cavernous nerve injury in rats that mimics radical prostatectomy in humans.

ABSTRACT

OBJECTIVE: To investigate the early and delayed effects of cavernous nerve electrocautery injury (CNEI) in a rat model, with the expectation that this model could be used to test rehabilitation therapies for erectile dysfunction (ED) after radical prostatectomy (RP). MATERIALS AND METHODS: In all, 30 male Sprague-Dawley rats were randomly divided equally into two groups (15 per group). The control group received CNs exposure surgery only and the experimental group received bilateral CNEI. At 1, 4 and 16 weeks after surgery (five rats at each time point), the ratio of maximal intracavernosal pressure (ICP) to mean arterial pressure (MAP) was measured in the two groups. Neurofilament expression in the dorsal penile nerves was assessed by immunofluorescent staining and Masson's trichrome staining was used to assess the smooth muscle to collagen ratio in both groups. RESULTS: At the 1-week follow-up, the mean ICP/MAP was significantly lower in the CNEI group compared with the control group, at 9.94% vs 70.06% (P < 0.05). The mean ICP/MAP in the CNEI group was substantially increased at the 4- (35.97%) and 16-week (37.11%) follow-ups compared with the 1-week follow-up (P < 0.05). At all three follow-up time points, the CNEI group had significantly decreased neurofilament staining compared with the control group (P < 0.05). Also, neurofilament expressions in the CNEI group at both 4 and 16 weeks were significantly higher than that at 1 week (P < 0.05), but there was no difference between 4 and 16 weeks (P > 0.05). The smooth muscle to collagen ratio in the CNEI group was significantly lower than in the control group at the 4- and 16-week follow-ups (P < 0.05), and the ratio at 16 weeks was further reduced compared with that at 4 weeks (P < 0.05). CONCLUSIONS: In the CNEI rat model, we found the damaging effects of CNEI were accompanied by a decline in ICP, reduced numbers of nerve fibres in the dorsal penile nerve, and exacerbated fibrosis in the corpus cavernosum. This may provide a basis for studying potential preventative measures or treatment strategies to ameliorate ED caused by CNEI during RP.