Pelvic nerve injury negatively impacts female genital blood flow and induces vaginal fibrosis-implications for human nerve-sparing radical hysterectomy.

Abstract

This study sought to develop a novel animal model to study the impact of nerve-sparing radical hysterectomy (NSRH) on female genital blood flow. In vivo animal study. Thirty Sprague-Dawley female rats. Female rats underwent either unilateral pelvic nerve (PN) crush (PNC; n=9), or crush of both the PNs and all efferent nerves in the pelvic plexus ('clock-nerve crush', CNC; n=9). Under anaesthesia, we electrically stimulated the crushed PN at 3 and 10days after crush while monitoring blood pressure and recording clitoral and vaginal blood flows by laser Doppler. Uninjured PNs were stimulated as an internal control. Twelve additional rats were assigned either to bilateral PNC or sham surgery, and genital tissues were processed 10days after injury for invitro analysis. Genital blood flow, nNOS, eNOS, collagen I-III. Stimulation of the crushed PN in both groups subjected to PNC and CNC induced significantly lower peak genital blood flow at 3 and 10days (P<0.05) compared to stimulation of the non-crushed control PN. The immunofluorescence and Western blot analyses revealed that all injured rats exhibited more vaginal collagen III and collagen I than rats did that ad undergone sham surgeries (P<0.05). PCN reduced nNOS expression in both clitoral and vaginal tissue. Based on our study it may be hypothesised that NSRH might cause reductions of genital blood flow and vaginal fibrosis due to neurapraxia of the pelvic nerve and reductions of nNOS nerve fibres in clitoral and distal vaginal tissue. Pelvic nerve neurapraxia during nerve-sparing radical hysterectomy could lead to sexual arousal dysfunction.