Yongdamsagan-tang, a traditional herbal formula, is used widely for the treatment of inflammation and viral diseases. In this study, we investigated whether Yongdamsagan-tang water extract (YSTE) affects testosterone propionate- (TP-) induced benign prostatic hyperplasia (BPH) in a rat model. To induce BPH, rats were injected subcutaneously with 10 mg/kg of TP every day. YSTE was administrated daily by oral gavage at doses of 200 and 500 mg/kg along with the TP injection. After 4 weeks, prostates were collected, weighed, and analyzed. The relative prostrate weight was significantly lower in both YSTE groups (200 and 500 mg/kg/day) compared with the TP-induced BPH group. YSTE administration reduced the expression of proliferation markers PCNA, cyclin D1, and Ki-67 and the histological abnormalities observed in the prostate in TP-induced BPH rats. YSTE attenuated the increase in the TP-induced androgen concentration in the prostate. The YSTE groups also showed decreased lipid peroxidation and increased glutathione reductase activity in the prostate. These findings suggest that YSTE effectively prevented the development of TP-induced BPH in rats through antiproliferative and antioxidative activities and might be useful in the clinical treatment of BPH
