In vivo comparison of pirfenidone and phosphodiesterase type 5 inhibitors in a rat model of peyronie disease

This study aimed to investigate the histopathological and hemodynamic effects of pirfenidone on an experimental model of Peyronie's disease in rats, and to compare with tadalafil (phosphodiesterase type-5 inhibitor). Forty-two male Sprague-Dawley rats, aged 12 weeks and weighing between 250 and 300 grams, were randomly assigned to five groups. An experimental model of Peyronie's disease was established by injecting Transforming Growth Faktör- β dissolved in saline into the tunica albuginea of the rats, while the control group received saline only. The control and Peyronie groups did not receive any treatment, while the other three groups were administered tadalafil 5 mg/kg/day and pirfenidone 30 and 300 mg/kg/day. After a 4-week treatment period, cavernous nerve stimulation was performed under general anesthesia, and intracavernosal and intra-arterial pressures were measured. The penile tissues were then excised, and the rats were sacrificed. The tissues were sent to a pathology for histopathological evaluation. The findings indicated that the highest basal intra cavernosal pressure was recorded in the tadalafil group, while the 300 mg/kg pirfenidon group exhibited the lowest score; this difference was statistically significant (p=0,016). Although maximal intra cavernosal pressure/mean arterial pressure ratio was highest in the 300 mg/kg pirfenidon group, this difference was not statistically significant among groups. The fibrosis score in the control group was significantly lower than in the Peyronie group. All treatment groups showed statistically significant improvements in fibrosis score, collagen/smooth muscle and type III/type I collagen ratio compared to the Peyronie group. The effects of pirfenidone showed a dose-dependent enhancement. In conclusion, the treatments evaluated in this study showed an anti-fibrotic effect on the experimental Peyronie's disease model; however, no statistically significant improvement in erectile function was observed.