Shoutai Wan regulates maternal-fetal immune tolerance in lactate dehydrogenase A knockdown model mice to prevent miscarriage.

PROBLEM: Maternal-fetal immune tolerance is vital for a healthy pregnancy. However, the metabolic factors governing this balance are not yet clear. This study investigates the role of LDHA in this process and explores how Shoutai Wan (STW) regulates uterine immune cells through LDHA. METHODS: A uterine-specific LDHA-knockdown model was established by injecting AAV9-Ldha-RNAi into the uterus of CBA/J mice. Following STW pretreatment, female mice were mated with male BALB/c mice. Gravid uteri were collected on gestational days 6.5, 10.5, and 14.5. Embryo counts were recorded, and tissue morphology was observed using HE staining. Uterine immune cell populations including CD4+ T cells, CD8+ T cells, M1/M2-like macrophages, Th1/Th2 cells, Tregs, and NK cells were analyzed by immunohistochemistry and flow cytometry. IL-4, Foxp3, IFN-γ, and TGF-β1 expression were quantified by qRT-PCR and Western blot. RESULTS: Uterine LDHA knockdown decreased embryo number and disrupted maternal-fetal interface morphology. STW treatment reversed these effects. IHC showed that STW increased CD4+ T cells, F4/80+ macrophages, and NK cells at the maternal-fetal interface of sh-Ldha mice and reduced CD8+ T cell infiltration. Flow cytometry further revealed that STW increased the absolute numbers of uterine Tregs and NK cells in early and mid‑pregnancy, whereas reducing Th1 cell counts at all three time points. Both Western blot and qRT‑PCR analyses confirmed that STW upregulated the protein and mRNA expression of LDHA, IL‑4, TGF‑β1, and Foxp3, while suppressing that of IFN‑γ at the maternal‑fetal interface. CONCLUSION: Uterine LDHA inhibition disrupts maternal-fetal immune tolerance in pregnant CBA/J mice. STW treatment restores this balance in sh-Ldha mice, supporting a successful pregnancy.