Phytoestrogen-like effect of Siwu Decoction and molecular mechanism: based on network pharmacology and in vivo experiment

Abstract

This study explored the phytoestrogen-like effect of Siwu Decoction(SWD) and the estrogen receptor(ER)-mediated molecular mechanism based on network pharmacology and in vivo experiment. The active components and targets of SWD were retrieved from Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform(TCMSP), and related targets of "estrogen" from GeneCards and Online Mendelian Inheritance in Man(OMIM). Cytoscape and STRING were employed to construct the protein-protein interaction(PPI) network and "chemical component-target-disease" network and core targets were identified, followed by Gene Ontology(GO) term enrichment and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment of the core targets by R software. For the in vivo experiment, the 22-day-old SD female rats were treated(ig) with SWD for 4 days. Via hematoxylin-eosin(HE) staining, the morphological changes of rat uterus were observed. Reverse transcriptase-polymerase chain reaction(RT-PCR) was performed to detect mRNA expression of ER subtypes, estrogen-related targets, and the main regulatory factors in the estrogen signaling pathway. The results indicated 74 targets of SWD exerted phytoestrogen-like effect. KEGG pathway enrichment result suggested that estrogen signaling pathway was closely related to the phytoestrogen-like effect of SWD. Rats in SWD group demonstrated significantly thickened endometrium and significantly decreased expression of ERα, ERβ, and G protein-coupled estrogen receptor(GPER) mRNA in ovarian tissue. In addition, significant lowering of ERα and ERβ mRNA expression and significant rise of GPER mRNA expression in uterine tissue were observed in the SWD group. The expression of mitogen-activated protein kinase(MAPK) p38, MEK1/2 and extracellular signal-regulated kinase(ERK)1/2 mRNA was significantly low while that of epidermal growth factor receptor(EGFR) mRNA was significantly high in both ovarian and uterine tissues of SWD group compared with those in the control group. In conclusion, the phytoestrogen-like effect of SWD is closely related to the estrogen signaling pathway. The result lays a basis for revealing molecular mechanism of SWD in the treatment of gynecological diseases.