Oral exposure to low-dose bisphenol A aggravates testosterone-induced benign hyperplasia prostate in rats

The declining level of androgen during aging, associated with an inclining level of estrogen, has been hypothesized to be important in the development of benign prostatic hyperplasia (BPH). Within physiologic range, increasing estrogen levels can stimulate prostate to develop and permanently increase prostate size. As an estrogenic endocrine disruptor, bisphenol A (BPA) might be stimulatory to prostate development. We further hypothesized that low dose BPA could induce hyperplasia prostate to proliferate and aggravate the symptom of BPH in male SD rats. BPH was induced by testosterone and then treated with BPA (10, 30, or 90 mu g/kg, i.g., daily), 17 beta-estradiol (E(2); 50.0 mu g/kg, s.c., daily), or vehicle for 4 weeks. We found that weight and volume in rats treated with low dose BPA (10 mu g/kg) was higher than that of model control, and BPA significantly increased the relative weight of prostate (p < 0.01). For prostate lobes, BPA 10 mu g/kg/day significantly increased relative weight of ventral prostate (VP), weight and relative weight of dorsolateral prostate (DLP) (p < 0.05). And histopathology results showed that height of epithelial cell (HEC) of VP and DLP in BPA group were significantly higher than that of model control (p < 0.01). BPA could also decrease testostertone level and increase prostate-specific antigen level. E(2) treatment also showed an obvious effect on relative weight of VP and DLP, HEC, and hormone levels. We concluded that environment exposure to low dose of BPA may induce prostate to proliferate and aggravate testosterone-induced benign hyperplasia prostate in rats.