Objective: To investigate the effects of different concentrations of Rauwolfia extract (RE) on the proliferation of prostate cells in the rat model of benign prostatic hyperplasia (BPH).
Methods: We randomly divided 48 male SD rats into six groups of an equal number, BPH model control, finasteride, low-concentration RE, medium-concentration RE, high-concentration RE and normal control, and established a BPH model in the former five groups by subcutaneous injection of testosterone propionate following castration. We treated the rats of the finasteride and RE groups intragastrically with finasteride solution at 5 mg/kg and RE at 5, 10 and 20 mg/kg respectively, and those of the model control and normal control groups with an equal dose of normal saline, all once a day for 28 consecutive days. Then, we killed all the animals, collected their prostate tissue, obtained the wet weight and volume of the prostate, the prostate index and the contents of serum T and dihydrotestosterone (DHT), observed the morphological changes of the prostate tissue by HE staining, counted the glands in the prostate tissue, measured the intraglandular area, and determined the expressions of PCNA and α-SMA by immunohistochemistry.
Results: Compared with the rats of the normal control group, the BPH model controls showed significantly increased wet weight (［0.923 ± 0.15］ vs ［1.455 ± 0.52］ g, P < 0.05), volume (［1.035 ± 0.29］ vs ［1.687 ± 0.31］ ml, P < 0.05) and index of the prostate (［0.23 ± 0.04］% vs ［0.37 ± 0.15］%, P < 0.05), dilation, hyperemia and edema of the prostatic stroma and vessels, and proliferation rate of the prostatic cells, but remarkably decreased number of glands (［20.35 ± 3.83］ vs ［12.56 ± 2.58］, P < 0.05), epithelial thickness (［39.76 ± 5.20］ vs ［19.52 ± 1.52］ μm, P < 0.05) and intraglandular area (［12.3 ± 1.21］ vs ［5.96 ± 0.34］ ×103μm2, P < 0.05). In comparison with the BPH model controls, the animals treated with RE, especially in the high-concentration RE group, exhibited marked decreases in the weight (［1.455 ± 0.52］ vs ［0.862 ± 0.31］ g, P < 0.05), volume ( ［1.687 ± 0.31］ vs ［0.952 ± 0.28］ ml, P < 0.05) and index of the prostate (［0.37 ± 0.15］% vs ［0.22 ± 0.07］%, P < 0.05), dramatic improvement in the number of glands (［12.56 ± 2.58］ vs ［18.36 ± 1.25］, P < 0.05), epithelial thickness (［39.76 ± 5.20］ vs ［19.04 ± 3.89］ μm, P < 0.05) and intraglandular area (［5.96 ± 0.34］ vs ［10.25 ± 0.98］ ×103μm2, P<0.05］, P < 0.05), remarkable down-regulation of the expressions of PCNA and α-SMA, and significant reduction of the contents of serum T (［19.147 ± 3.214］ vs ［6.016 ± 1.978］ ng/ml, P < 0.05) and DHT (［9.052 ± 0.633］ vs ［2.532 ± 0.386］ ng/ml, P < 0.05).
Conclusion: Rauwolfia extract can inhibit the proliferation of prostate cells and relieve BPH symptoms in a concentration-dependent manner in rats with BPH.
Keywords: Rauwolfia extract; benign prostatic hyperplasia; proliferating cell nuclear antigen; α-smooth muscle actin; rat.