Anti-proliferative effect and mechanisms of Peony pollen on BPH via inhibition of inflammatory factors, oxidative damage and modulation of gut microbiota and SCFAs metabolism

Background: Peony pollen (PP) has long been used as a functional food and herbal medicine. However, the potential protective effect and mechanisms of PP on benign prostatic hyperplasia (BPH) are still unclear. This study aims to explore the therapeutic effect and potential mechanisms of PP on BPH. Methods: The rat model of BPH was induced by subcutaneous injection of testosterone propionate (TP). Meanwhile, the model rats were treated with PP, and physiological and biochemical indexes, the steroid 5 alpha reductase 2 (SRD5A2), proliferating cell nuclear antigen (PCNA) and androgen receptor (AR) expressions, gut microbiota and short-chain fatty acids (SCFAs) were measured. Results: The results showed that the wet weight of prostate tissue and the thickness of epithelium decreased treated with PP significantly. In addition, the PP also adjusted the androgen levels, down-regulated the SRD5A2, PCNA and AR expressions, inhibited the expression of inflammatory factors including interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α), interleukin 1β (IL-1β) and reduced oxidative damage in BPH rats. It is worth noting that PP can obviously regulate the gut microbiota disorder of BPH rats, increase the abundance of beneficial bacteria (e.g., Romboutsia), reduce the abundance of pathogenic bacteria (e.g., norank_f_Oscillospiraceae), and stimulate the increase of SCFAs content. Conclusions: These data showed that PP can resist abnormal proliferation of the prostate by down regulation of SRD5A2, PCNA and AR expressions, attenuating oxidation stress and inflammatory damages and directly regulate the gut microbiota, especially the Firmicutes, and increased the level of SCFAs to ameliorate BPH. Therefore, PP might be an excellent natural plant for the development of BPH-related drugs or dietary supplements.