Histopathological changes and nitric oxide synthase activity in corpus cavernosum from rats with neurogenic erectile dysfunction

Objective To investigate changes in histology and nitric oxide synthase (NO S) activity in cavernosal tissues from rats with neurogenic erectile dysfun ction induced experimentally. Materials and methods Twenty-four adult male Sprague-Dawley rats were divid ed equally into three groups and underwent a sham operation (control, group 1), unilateral (group 2) or bilateral (group 3) cavernosal nerve resection , Three months later they were killed and the cavernosal tissues analysed h istologically by light and transmission electron microscopy, with NOS activ ity detected using an NADPH-diaphorase staining technique. Results On light and electron microscopy, while penile nerves and cavernosa l smooth muscle cells had a normal morphological appearance in the eight co ntrol rats, there were degenerative changes of the myelinated penile nerves and axonal fibrosis in groups 2 and 3. However, these changes were not sig nificant. Using NADPH-diaphorase staining, NOS activity was detected in all three groups in endothelial cells and cavernosal structures, However, the staining was more intense in endothelial cells and cavernosal muscles of ra ts in group 2 than in the other groups, Conclusion NOS activity was increased in the cavernosal tissue after cavern osal denervation, but the pharmacological action of nitric oxide may be imp aired.