Lycopus lucidus Extract Attenuates Testosterone Propionate-Induced Benign Prostatic Hyperplasia in Rats

Background/Objectives: Benign prostatic hyperplasia (BPH) is a common age-related disorder in elderly men and a major cause of lower urinary tract symptoms. Lycopus lucidus Turcz. ex Benth. has been traditionally used in East Asian medicine, but its effects on BPH have not been investigated. This study evaluated the effects of L. lucidus extract (LLE) on testosterone propionate (TP)-induced BPH in rats and explored associated changes in androgen metabolism. Methods: Male Sprague-Dawley rats were orchiectomized except for the sham group and injected with TP (3 mg/kg, s.c.) for 28 days. During TP exposure, rats received oral LLE (100 or 200 mg/kg/day), finasteride (1 mg/kg/day), or vehicle. Prostate weight, prostate index, and histological changes in the ventral prostate were evaluated. Serum testosterone and dihydrotestosterone levels were measured using an enzyme-linked immunosorbent assay. The protein expression of 5α-reductase type 2, aromatase, Bax, and Bcl-2 in the ventral prostate tissue was analyzed by Western blotting. Results: LLE (200 mg/kg) significantly reduced prostate weight and prostate index and improved histological alterations, comparable to finasteride. LLE increased serum testosterone levels and decreased the dihydrotestosterone/testosterone ratio. Expression of 5α-reductase type 2 and aromatase in the ventral prostate tissue was significantly downregulated, while Bax and Bcl-2 expression and the Bax/Bcl-2 ratio remained unchanged. Conclusions: LLE attenuated TP-induced prostatic hyperplasia in rats, suggesting that modulation of androgen metabolism may contribute to its anti-hyperplastic effects. These findings support further investigation of L. lucidus extract in BPH.