Effects of finasteride on the vascular surface density, number of microvessels and vascular endothelial growth factor expression of the rat prostate.

Introduction: Finasteride is a 5-alpha-reductase inhibitor used in the medical treatment of benign prostatic hyperplasia (BPH) and appears to be effective in treating prostatic bleeding secondary to BPH. The exact mechanism of this effect is not known. The aim of this study was to evaluate the effects of finasteride on the vascular surface density (VSD), number of microvessels (NVES) and vascular endothelial growth factor (VEGF) expression of the rat prostate.

Materials And Methods: Nineteen adult male rats were used. Finasteride was given to 14, and there were 5 in the control group. Finasteride 80 mg/kg was administered daily via orogastric tube as a suspension for three months. Rats were sacrificed and vascular structures of the prostates were labelled immunohistochemically using CD31 antibodies. VSD and NVES of the prostates were assessed by means of a peroxidase labeled streptavidin-biotin method. VEGF expression was examined by immunohistochemistry using VEGF monoclonal antibody.

Results: Mean prostatic weights were decreased significantly in rats given finasteride (p=0.0001). Although an increase in VSD was detected in the finasteride group it was not significant (p=0.26). NVES was significantly increased in the finasteride group (p=0.033). No significant difference was detected between the two groups in terms of VEGF expression (p=0.48).

Conclusion: Finasteride does not seem to decrease VSD, NVES and VEGF expression at the level of the rat prostate. The effect of reduction of bleeding in BPH is likely to be due to its effect on shrinking glandular hyperplasia which might enhance vessel wall stability rather than decreasing overall vascularity.