The Feasibility Of Erectile Function Recovery After Partial Obturator Nerve To Cavernous Nerve Rerouting In Rats

Objective:To investigate the feasibility of erectile function recovery after reroutingproximal partial obturator nerve to distal cavernous nerve through end-to-end neurorrhaphyin rats,and provide the theoretical basis and experimental evidence on the new nervererouting method for the treatment of neurogenic erectile dysfunction.Methods:Thirty male Sprague-Dawley rats(weighing220g-250g) were randomly dividedinto three groups: the bilateral rerouting group (n=10) had a0.5cm segment of proximalcavernous nerve excised and about1/3beam of obturator nerve transectedbilaterally,followed by rerouting proximal partial obturator nerve to distal cavernous nervethrough end-to-end neurorrhaphy; the nerve ablation group(n=10),rats received the sameoperation as the bilateral rerouting group but without coaptation; the sham operation group(n=10) underwent pelvic exploration without transection of the cavernous nerve andobturator nerve. Three months postoperatively,5μl0.25%carbocyanine dyes(DiI) wasinjected into the corpus cavernosum of five rats in each group for retrograde tracing.Andtwelve days after the injection,0.5cm length of the distal regenerated nerves were collectedto observe the degeneration and regeneration of the axons by light microscopy and electronmicroscopy;L1-S1spinal cords were also collected separately after the rats fixed by4%paraformaldehyde and DiI labeled neuron cells would be observed in spinal cord underfluorescence microscope.The cavernous nerves of the other rats in each group wereelectrical stimulated to monitor the intracavernous pressure(ICP).Results: Slightly enlargement on the anastomotic site was observed three months postoperative and its distal segment grows rounded in the bilateral rerouting group. Lightmicroscopy observation on the distal segment showed a large number of ringaxons.Regenerated myelinated and unmyelinated axons were observed by electronmicroscopy on the distal cavernous nerves and myelin sheath arranged lamellar.While onlyWaller degeneration could be observed on the transected nerve in the ablation group withmyelin sheath disappeared.The DiI labeled motoneurons in the rerouting group weresignificantly observed in the part of ventral horn of the L2-L4spinal cords,compared withthat labelled neurons in sham operation group were mainly concentrated in theintermediolateral column at L1-L2levels and no neurons were labelled in the ablationgroup at the same spinal levels.Electrical stimulation of the cavernous nerve producedenlargement or erection of the penis in the rerouting group and the resulting ICP valuesincreased by an average of about32.93mmHg which was about55.9%of the values in thesham operation group.But they were significantly higher than the ablation group in whichonly6.26mmHg was produced(P<0.05).Conclusion: Erectile function recovery was realized or partially realized after partialobturator nerve to cavernous nerve rerouting in rats.