Preventive vs. therapeutic effects of Shoutai Wan: Maintaining an acidic microenvironment at the maternal-fetal interface to promote angiogenesis and minimize pregnancy loss in RSA mice

ETHNOPHARMACOLOGICAL RELEVANCE: The classic TCM prescription, Shoutai Wan (STW), is extensively used in clinical settings to manage threatened miscarriage and Recurrent spontaneous abortion (RSA). The complexity of pregnancy physiology, coupled with diverse etiologies, and the specificity of energy metabolism for normal embryo attachment and development, pose challenges to clinical diagnosis and treatment. The specific molecular mechanisms of how STW regulates these biological processes and contributes to the treatment of RSA remain to be elucidated. AIM OF THE STUDY: This study aims to investigate the causes of early pregnancy loss in RSA mice and explore how STW mitigates this loss. MATERIALS AND METHODS: An RSA mouse model will be established and treated with STW and Dydrogesterone (DYD). Embryo loss will be quantified on the 14th day of pregnancy, and embryos will be collected on the 6th and 10th days to observe the embryonic condition and assess pathological changes. The study will analyze aerobic glycolysis and angiogenesis at the maternal-fetal interface (MFI). Additionally, STW on a knockdown LDHA mouse model and Human Endometrial Microvascular Endothelial Cells (HEMECs) in vitro will also be examined to verify the mechanism. RESULTS: Compared with the control group, the RSA group exhibited significant embryo loss, and reduced levels of aerobic glycolysis at the MFI, the precarious acidic microenvironment (AME), and the PI3K/AKT/mTOR signaling axis downregulated, leading to impaired angiogenesis, which ameliorated following STW treatment. STW treatment enhanced key aerobic glycolysis enzymes-HK2, PKM2, LDHA-and lactate levels, thereby maintaining the AME and upregulating the PI3K/AKT/mTOR axis. This, in turn, promoted the expression of angiogenesis-related factors (VEGFA and VEGFR2) at the MFI, thereby improving angiogenesis, and the same was seen in sh-LDHA mice. In vitro studies confirmed that STW could counteract the glycolysis decline caused by increased oxygen levels, a recovery that was impaired after LDHA knockdown or PI3K inhibition. CONCLUSIONS: In RSA mice, disturbances in aerobic glycolysis at the MFI prevent the maintenance of a stable AME, thus impairing angiogenesis and leading to embryo loss, and STW effectively improve early pregnancy outcomes, and laying the foundation for uterine spiral artery remodeling.