The effect of pentoxifylline on penile cavernosal tissues in ischemic priapism-induced rat model

Priapism is defined as persisting (>4 h), painful and abnormal tumescence that can occur without sexual stimulation. Three subtypes priapisms are seen-the non-ischemic priapism, intermittent and the ischemic priapism. In ischemic priapism, there is an abnormality in the veno-occlusive mechanism, resulting in venous stasis and accumulation of deoxygenated blood within the penile cavernosal tissue. Cavernosal tissue necrosis develops after extended period of ischemia and is eventually replaced by fibrotic tissue. It may results in erectile dysfunction if not treated promptly. Although, standard treatment of the ischemic priapism is penile aspiration and intracavernosal alpha-adrenergic agents, new oral agents have been investigated to reduce the cavernosal damage. In this study, the effect of different doses of pentoxifylline on cavernosal tissues was evaluated.

Thirty-six male Wistar albino rats, age 5.5-6 months and weighing 250-300 g, were used in this study. The rats were randomly divided into five groups. In Group 1 (n = 7), the control group, only penectomy was performed. In Group 2 (n = 8), after 1 h of ischemic priapism, penectomy was performed. Group 3 (n = 7) received daily a 10 mg oral pentoxifylline for 4 weeks after 1 h of ischemic priapism, group 4 (n = 7) received a daily 30 mg oral pentoxifylline for 4 weeks after 1 h of ischemic priapism, and group 5 (n = 7) received a daily 100 mg oral pentoxifylline for 4 weeks after 1 h of ischemic priapism. At the completion of a 4-week period, penile tissues were obtained. Before penile tissues were obtained, intracavernosal pressures measured with electrical field stimulation and smooth muscle collagen ratio were evaluated pathologically.

Electrical field stimulation-induced intracavernosal relaxation decreased in group 2 compared with group 1 (p < 0.05). Electrical field stimulation-induced relaxation enhanced in the group 3, 4 and 5 compared to group 2 (p < 0.05). In group 2, the collagen density was significantly higher than group 1. Administration of pentoxifylline reduced the collagen density caused by ischemic priapism in groups 3, 4 and 5 compared with group 2.

The results of the present study showed that ischemic priapism caused damage in the penile tissues of rats, and treatment with pentoxifylline reduced the harmful effects of ischemic priapism.