The efficacy and mechanism of Angelica sinensis (Oliv.) Diels root aqueous extract based on RNA sequencing and 16S rDNA sequencing in alleviating polycystic ovary syndrome

Background: Polycystic ovary syndrome (PCOS) leads to persistent anovulation, hyperandrogenism, insulin resistance, and polycystic ovary, and is mainly characterized by menstrual disorders, and reproductive dysfunction. Angelica sinensis (Oliv.) Diels root has been used in many classical formulas of traditional Chinese medicine, and is commonly used to treat various gynecological diseases.Purpose: To investigate the protective effect of water extract of A. sinensis root (WEA) on PCOS rats, and the mechanism by RNA sequencing, and 16S rDNA sequencing. Methods: The PCOS rat model was established by letrozole combined with high-fat diet (gavage; 2 months), and treated with WEA (gavage; 2 g/kg, 4 g/kg or 8 g/kg; 1 month). To evaluate the therapeutic effect of WEA on PCOS rats, vaginal smear, hematoxylin-eosin staining, and biochemical indicators detection were performed. The rat ovarian tissue was analyzed by RNA sequencing, and the results were verified by qRT-PCR, and Western blot. 16S rDNA sequencing was used to analyze the gut microbiota of rats. Results: The results of the vaginal smear, and hematoxylin-eosin staining showed that WEA improved estrous cycle disorder, and ovarian tissue lesions. WEA (4 g/kg or 8 g/kg; 1 months) alleviated hormone disorders, insulin resistance, and dyslipidemia. RNA sequencing showed that WEA intervention significantly changed the expressions of 2756 genes, which were enriched in phosphatidylinositol3-kinase/phosphorylated protein kinase B (PI3K/AKT), peroxisome proliferator-activated receptor (PPAR), mitogen-activated protein kinase (MAPK), AMP-activated protein kinase (AMPK), and insulin signaling pathways. 16S rDNA sequencing found that WEA increased the species diversity of gut microbiota, and regulated the abundance of some microbiota (genus level: Dubosiella, Bifidobacterium, Coriobacteriaceae (UCG-002), and Treponema; species level: Bifidobacterium animalis, Lactobacillus murinus, and Lactobacillus johnsonii). Conclusion: WEA regulated hormone, and glycolipid metabolism disorders, thereby relieving the PCOS induced by letrozole combined with high-fat diet. The mechanism was related to the regulation of PI3K/AKT, PPAR, MAPK, AMPK, and insulin signaling pathways in ovarian tissues, and the maintenance of gut microbiota homeostasis. Clarifying the efficacy and mechanism of WEA in alleviating PCOS based on RNA sequencing and 16S rDNA sequencing will guide the more reasonable clinical use of WEA.