17beta-estradiol affects proliferation and apoptosis of rat prostatic smooth muscle cells by modulating cell cycle transition and related proteins.

Abundant evidence indicates that estrogens have an important role in the pathology of benign prostatic hyperplasia (BPH). To investigate the effect of 17beta-estradiol (E2) on the proliferation and apoptosis of prostatic smooth muscle cells (PSMCs), rat PSMCs were obtained and exposed to gradient concentrations (0.1-100 nmol/l) of E2 over varying amounts of time. The progression of cell cycle, cellular apoptosis, cyclin D1, Bcl-2 and Bax proteins were detected. The data show that the effect of E2 on rat PSMCs is bilateral: it promotes cell proliferation by enhancing the expression of cyclin D1, which accelerates G1 to S phase transition; on the other hand, it induces apoptosis of the cells by up-regulating the expression of Bax. We thus suggest that an increase in estrogen may exert a launching effect in the pathology of BPH.