Inhibitory effect of rape pollen supercritical CO(2) fluid extract against testosterone-induced benign prostatic hyperplasia in rats

Benign prostatic hyperplasia (BPH) can lead to lower urinary tract symptoms. Rape pollen is an apicultural product that is composed of nutritionally valuable and biologically active substances. The aim of the present study was to investigate the protective effect of rape pollen supercritical CO(2) fluid extract (SFE-CO(2)) in BPH development using a testosterone-induced BPH rat model. BPH was induced in the experimental groups by daily subcutaneous injections of testosterone for a period of 30 days. Rape pollen SFE-CO(2) was administered daily by oral gavage concurrently with the testosterone injections. Animals were sacrificed at the scheduled termination and the prostates were weighed and subjected to histopathological examination. Testosterone, dihydrotestosterone (DHT), 5α-reductase and cyclooxygenase-2 (COX-2) levels were also measured. BPH-induced animals exhibited an increase in prostate weight with increased testosterone, DHT, 5α-reductase and COX-2 expression levels. However, rape pollen SFE-CO(2) treatment resulted in significant reductions in the prostate index and testosterone, DHT, 5α-reductase and COX-2 levels compared with those in BPH-induced animals. Histopathological examination also demonstrated that rape pollen SFE-CO(2) treatment suppressed testosterone-induced BPH. These observations indicate that rape pollen SFE-CO(2) inhibits the development of BPH in rats and these effects are closely associated with reductions in DHT, 5α-reductase and COX-2 levels. Therefore, the results of the present study clearly indicate that rape pollen SFE-CO(2) extract may be a useful agent in BPH treatment.