Anthocyanins extract from bilberry enhances the therapeutic effect of pollen of Brassica napus L. on stress-provoked benign prostatic hyperplasia in restrained mice

Clinical research has revealed that stressed men are susceptible to develop benign prostatic hyperplasia (BPH). In this study, restraint-stress mice model was employed to mimic the physiological conditions of the population that was susceptible to develop BPH. Male mice were subjected to restraint stress after being subcutaneously injected with testosterone propionate (TP) for 14 d. Results demonstrated that TP-induced BPH was significantly aggravated by restraint stress, as manifested by increases of prostate index, serum testosterone level, and prostate 5α-reductase (5AR) and serum acid phosphatase (ACP) activities. These findings were further supported by results of prostate pathological examination. However, we found that anthocyanins extract (AE) from bilberry (Vaccinium myrtillus L.) had additive effect with pollen of Brassica napus L. (PBN), a widely used folk remedy for BPH in traditional Chinese medicine, on stress-provoked BPH in mice. The mechanism was associated with the protective effects of AE against stress-induced oxidative damage, as indicated by decreased lipid peroxidation level, increased oxygen radical absorbance capacity (ORAC) and glutathione (GSH) content, along with elevated superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities. Our results proved that stress-induced oxidative damage promoted the development and aggravation of BPH, while antioxidative defense contributed to the amelioration of BPH.