Potential ameliorative effects of epigallocatechin-3-gallate against testosterone-induced benign prostatic hyperplasia and fibrosis in rats

Green tea is among the most popular beverages in the world and is an important source of phytoestrogens. Epigallocatechin-3-gallate (EGCG) is the major polyphenol in green tea. The aim of this study was to investigate the anti-benign prostatic hyperplasia (BPH) activity and underling mechanisms of EGCG in testosterone-induced BPH rats and in BPH-1 cells. Prostatic levels of oxidative stress and inflammation makers, as well as angiogenesis related growth factors were measured. Additionally, the prostatic levels of sex hormonal mediators (androgen receptor (AR), estrogen receptor (ER)-alpha and ER-beta), hypoxia-inducible factor (HIF)-1 alpha, transforming growth factor-beta 1 (TGF-beta 1), type I TGF-beta receptor (TGF-beta RI), Smad3, phosphorylation-Smad3 (p-Smad3), epithelial-mesenchymal transition (EMT) markers (E-cadherin, collagen-I, fibronectin and alpha-SMA) and microRNA (miR)-133a/b were analyzed by immunohistochemistry assay, western blot and/or quantitative RT-PCR. It was observed that EGCG attenuated the prostatic oxidative stress and inflammatory microenvironment, ameliorated prostatic hyperplasia and collagen deposition, reduced the levels of angiogenesis related growth factors, inhibited the over-expression of AR, ER-alpha, HIF-1 alpha, TGF-beta 1, TGF-beta RI and p-Smad3, enhanced the expression of ER-beta, increased the levels of miR-133a/b, as well as relieved prostatic EMT in rats. Both HIF-1 alpha inhibitor and EGCG decreased the expression of HIF-1 alpha and TGF-beta 1, as well as attenuated EMT in BPH-1 cells. It indicated that EGCG could attenuate testosterone-induced BPH and fibrosis.