AB157. The correlation between nNOS positive small branches of dorsal penis nerve and erectile function in bilateral cavernous nerve crush model of rat

PURPOSE: Cadavers’ evidences showed cavernous nerve (CN), a parasympathetic nerve, joint dorsal penis nerve (DPN) in the penis level. However, no reports elucidate the importance of the main or the small branches of the DPN in this model. The aim of the current study is to evaluate the association between nNOS positive small branches of DPN and erectile function in rat model. MATERIALS AND METHODS: Totally, 20 SD male rats were divided into five groups: the sham group and BCNC in 7, 14, 21 and 28 days. Erectile function was assessed by CN electrostimulation, and penile tissue was collected for histology. Immunohistochemical stains for the confirmation of nerve types were done. Finally, transmission electron microscopy (TEM) for Schwann cell damage and other detailed morphological changes were also performed. RESULTS: Erectile function was significantly decreased in injury group with the lowest after 14 days of BCNC. Partial recovery of the erectile function was noted within the next 14 days. In H&E stain, mean diameter, number of neuritis, inflammatory cells infiltration of the largest branch of DPN were similar in both sham group and injury group after different days of observation. No correlation was seen in the total number of nerve branches, sympathetic nerve branches and erectile function. However, nNOS positive small branches, parasympathetic nerve branches, showed significant positive correlation between the nerve number and erectile function. TEM showed Schwann cell damage and abnormalities of myelin sheath. CONCLUSIONS: Morphological changes after BCNC were seen in DPN in both light microscope and TEM. The current study support the evidences of CN, at least partially, joint with DPN in rat. In addition, small branches loss may be a representative feature of BCNC in DPN by light microscope. In addition, nNOS positive nerve branches were positively correlated with erectile function in rat.