Asteris Radix et Rhizoma suppresses testosterone-induced benign prostatic hyperplasia in rats by regulating apoptosis and inflammation

Ethnopharmacological relevance: Asteris Radix et Rhizoma (AR) refers to the roots and rhizomes of Aster tataricus L., which is widely distributed throughout East Asia. AR has been consumed as a traditional medicine in Korea, Japan and China for the treatment of urologic symptoms. To date, however, the therapeutic effect of AR on benign prostatic hyperplasia (BPH) has not been investigated. Aim of the study: The present study evaluated the therapeutic effects of AR on a testosterone-induced BPH rats. Materials and methods: We induced BPH to rats by subcutaneous injections (s.c) of testosterone propionate (TP) daily for four weeks. Rats were also administered daily oral gavage of AR (150 mg/kg) or vehicle. After four weeks of induction, all animals were euthanized humanely and their prostate glands were removed, weighed and processed for further analysis, including histopathological examination, real-time PCR, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and Western blot analysis. Results: Administration of AR to TP-induced BPH rats considerably reduced prostate weight and concentrations of serum testosterone and prostate dihydrotestosterone (DHT). Epithelial thickness and expression of proliferating cell nuclear antigen (PCNA) were markedly suppressed by AR-treatment in the rats. Furthermore, the expression of the B-cell lymphoma 2 (Bcl-2) were reduced and expression of the Bcl-2-associated X protein (Bax) increased, resulting in significant reduction in Bcl-2/Bax ratio. In addition, AR decreased the level of pro-inflammatory cytokines, including interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha). The expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) were reduced by AR treatment in a TP-induced BPH rat model. Conclusions: AR alleviates BPH by promoting apoptosis and suppressing inflammation, indicating that AR may be used clinically to treat BPH accompanied by inflammation.