Research On Restoration Of Erectile Function In Rats With Bilateral Cavernous Nerves Injuring

Objectives: To investigate whether reconstruction of cavernous nerve can restore erectile function using sural nerve as an interposition nerve graft.Methods: Forty-eight male Sprague-Dawley rats(3-4m old and 300-400g/each) were randomly divided into three groups: sham-operated controls(n=12) underwent pelvic exploration without transection of the cavernous nerve; nerve ablation group(n=12) had a 5mm segment of cavernous nerve excised bilaterally; graft group(n=12) had a 5mm segment of cavernous nerve excised bilaterally, followed by immediate microsurgical reconstruction with an interposition graft of sural neve. 2 and 4 moths postoperatively animals of each group were electrostimulated to the cavernosal nerves to determine potency. And fluorescent retrograde-transported dye Fluoro-Gold(FG) were injected into the penis. Five days after injection FG-labeled neuron cells in whole mounts of major pelvic ganglion were observed. Corpora cavernosa were harvested and nNOS-positive nerve fibers were examined with streptavidin-peroxidase immunohistochemistry techniques (SP method).Results: After two months electrical stimulation produced no erections in the nerve ablation or the graft group and 100% erections in the sham-operated group. The nNOS-positive nerve fibers were also have no significant difference between the graft group and the nerve ablation group(25.9+5.0,22.7+3.8, P>0.05). But the FG-labeled neurons in ganglion between the graft group and the ablation group have significant difference( 17.4+4.2,8.3+ 2.1.P<0.05). After four months, 43.75% of the grafted nerves produced erections upon electrical stimulation, which represented a significant difference compared with the nerve ablation group 6.25%. The nNOS-positive nerve fibers in the graft group(82.0+12.4) significantly differed from those in the ablation(27.3+4.1),and approximated the level of the sham-operated(94.5 + 7.4). The FG-labeled neurons alsoincreased in the graft group compared to those in ablation rats.Conclusions: cavernous nerve grafting in rats can be successful in restoring potency after surgical injury. Application of sural nerve as an interposition nerve graft to man may be indicated.