Cavernosal Smooth Muscle Function After Experimental Ischemic Priapism.

Objective: We aimed to investigate the role of apoptosis and its effects on cavernosal smoothmuscle (CSM) function after ischemic priapism (IP) in a rat model. Materials and Methods: Twelve adult Sprague-Dawley rats were assigned into two groups: The priapism and control groups. In all rats, erections were obtained by the vacuum method; however, in the priapism group, erections were maintained with a rubber band for 4 h to mimic priapism. After 14 days following this procedure, penile excision was performed and cavernosal tissues were investigated pharmacologically and histopathologically. Isometric tension changes due to several contractile and relaxant pharmacological agents were investigated with/without nitric oxide synthase (NOS) and guanylate cyclase (GC) inhibition. Results: Isometric contraction and relaxation responses due to the agents applied did not differ between the groups. However, with NOS and GC inhibition, the cavernosal tissues relaxed less in the priapism group than in the controls (p<0.05). Histopathological evaluation of the tissues revealed that the average apoptosis rates were greater in the priapism group than in the controls in both the CSM (60.3% vs. 31.8%) and cavernosal epithelia (40.2% vs. 7%). Conclusion: IP induction caused fibrosis by the apoptotic process in rat CSM. After IP, apoptosis in endothelial tissue was more evident than that in smooth muscle tissue in the corpus cavernosum. IP is likely to affect the NO pathway, resulting in a decrease in the NO-dependent relaxation in the cavernosal tissue. [ABSTRACT FROM AUTHOR]