Gut microbiota–insulin signaling axis mediates the therapeutic effects of TJZY decoction against PMOS

Introduction: TiaoJing ZhongYu (TJZY) Decoction is a traditional Chinese medicine formula used in the management of polyendocrine metabolic ovarian syndrome (PMOS). The molecular basis for its effects in PMOS, however, remains incompletely understood. This study assessed the therapeutic effects of TJZY Decoction in an obese rat model of PMOS and explored associated mechanisms using gut microbiome profiling, network pharmacology, and molecular biology approaches. Methods An obese rat model of PMOS was established using a high-fat diet and letrozole. Rats were assigned to Control, Model, low-dose TJZY (TJZY-L), high-dose TJZY (TJZY-H), and metformin (Met) groups. Body weight, estrous cyclicity, glucose tolerance, serum lipids, sex hormones, and liver and kidney function were assessed. Ovarian histopathology was evaluated by hematoxylin and eosin (H&E) staining. 16S rRNA sequencing characterized gut microbiota and predicted functional profiles. Ultra-high-performance liquid chromatography coupled with Q exactive tandem mass spectrometry (UHPLC-QE-MS/MS) identified TJZY Decoction constituents, while network pharmacology predicted therapeutic targets. Real-time quantitative PCR (RT-qPCR), Western blotting, and immunohistochemistry (IHC) assessed insulin signaling and the PI3K/AKT pathway. Results TJZY Decoction attenuated weight gain, improved glucose tolerance and dyslipidemia, restored estrous cyclicity, and ameliorated polycystic ovarian histopathology in PMOS rats. Compared with the Model group, TJZY-H reduced serum testosterone (T) by 13.8% ( P < 0.0001) and decreased the luteinizing hormone/follicle-stimulating hormone (LH/FSH) ratio by 46.1% ( P < 0.0001). Treatment was associated with increased Shannon and Simpson diversity indices and altered gut microbial composition. Mean relative abundances of Allobaculum and Treponema changed from 7.74% to 13.07% and from 14.08% to 0.15%, second is an increase in the proportions of Lactobacillus and Collinsella . UHPLC-QE-MS/MS annotated 93 putative constituents, and network pharmacology linked 32 candidate constituents to 67 shared targets. TJZY-H was also associated with increased ovarian PI3K and AKT phosphorylation and reduced expression of gluconeogenesis- and inflammation-related genes. Conclusion TJZY Decoction improved reproductive and metabolic abnormalities in rats with obesity-related PMOS. These effects may involve gut microbiota remodeling and enhanced insulin/PI3K/AKT signaling; reduced expression of gluconeogenesis- and inflammation-related markers was also observed. These findings associate TJZY Decoction treatment with gut microbiota remodeling and altered ovarian insulin/PI3K/AKT signaling; a causal link between them remains to be established.