Traditional Chinese Medicine Danzhi qing'e decoction inhibits inflammation-associated prostatic hyperplasia via inactivation of ERK1/2 signal pathway

Inflammation plays a critical role during benign prostatic hyperplasia (BPH) development. Danzhi qing'e (DZQE) decoction is a traditional Chinese medicine that has been widely used for estrogen and androgen-related diseases. However, its effect on inflammation-related BPH remains unclear.To investigate the effect of DZQE on inhibition of inflammation-related BPH, and further identify the possible mechanism involved.Experimental autoimmune prostatitis (EAP)-induced BPH was established and then 2.7 g/kg of DZQE was administrated orally for 4 weeks. The prostate sizes, weights and prostate index (PI) values were recorded. Hematoxylin and eosin (H&E) was performed for pathological analyses. Macrophage infiltrate was evaluated by Immunohistochemical (IHC). The inflammatory cytokine levels were measured by Rt-PCR and ELISA methods. The phosphorylation of ERK1/2 was examined by Western blot. The expression differences of mRNA expressions between EAP-induced and oestrogen/testosterone (E2/T)-induced BPH was investigated by RNA sequencing analyses. In vitro, human prostatic epithelial BPH-1 cells were stimulated with the conditioned medium from monocyte THP-1-derived M2 macrophages (M2CM), followed by treatment of Tanshinone IIA (Tan IIA), Bakuchiol (Ba), ERK1/2 antagonist PD98059 or ERK1/2 agonist C6-Ceramide. The ERK1/2 phosphorylation and cell proliferation were then detected by Western blotting and CCK8 assay.DZQE significantly inhibited the prostate enlargement and decreased PI value in EAP rats. Pathological analysis showed that DZQE alleviated prostate acinar epithelial cell proliferation by decreasing and reduction of CD68+ and CD206+ macrophage infiltration in the prostate. The levels of cytokines TNF-α, IL-1β, IL-17, MCP-1, TGF-β, and IgG in EAP rats' prostate or serum were significantly suppressed by DZQE as well. Moreover, mRNA sequencing data showed that the expressions of inflammation-related genes were elevated in EAP-induced BPH but not in E2/T-induced BPH. ERK1/2-related genes expression has been found in both E2/T and EAP-induced BPH. ERK1/2 is one of the core signal pathways involved in EAP-induced BPH, which was activated in EAP group but inactivated in DZQE group. In vitro, two active components of DZQE Tan IIA and Ba inhibited M2CM-induced BPH-1 cell proliferation, similarly to ERK1/2 inhibitor PD98059 did. Meanwhile, Tan IIA and Ba inhibited M2CM-induced ERK1/2 signal activation in BPH-1 cells. When re-activated the ERK1/2 by its activator C6-Ceramide, the inhibitory effects of Tan IIA and Ba on BPH-1 cell proliferation were blocked.DZQE suppressed inflammation-associated BPH via regulation of ERK1/2 signal by Tan IIA and Ba.