The Effect Of TGF-β1 On Adverse Pregnancy With Toxoplasma Gondii Infection

Aim:In this study, we want to explore the mechanism of the effect of exogenous TGF-β1 in adverse pregnancy outcomes after Toxoplasma infection and the TGF-β1/Smad3 signaling pathway in adverse pregnancy outcomes after Toxoplasma infection.Methods:There are four groups including pregnant mice with or without T. gondii infection, infected mice treated with TGF-β1 or TGF-β1 neutralizing antibody. The expression of the phosphorylation of Smad3 (pSmad3)、Foxp3 in CD4+T cells, inhibitory molecular CTLA-4, PD-1 on Tregs in all groups were analyzed by flow cytometry. The levels of IL-10 and TNF-a in placenta were measured using enzyme-linked immunosorbent assay (ELISA). Relationship between the expression of pSmad3 and the levels of Foxp3, CTLA-4, PD-1, IL-10, TNF-α was analyzed by Spearman’s correlation analysis.Results:The fetuses and placenta of normal pregnant mice developed normally. The fetuses and placenta of infected mice were small in size and had poor blood supplies and obvious hemorrhaging compared to the placenta from normal group. The expression of Foxp3 of CD4+T cells decrease and the expression of pSmad3 of CD4+T cells reduced significantly in infection pregnant group compared with the normal group. The proliferation of Treg cells significantly decreased at the same time. The pregnancy outcomes were improved after injection of exogenous TGF-β1 compared to infection group, the absorption rate dropped significantly, fetal weight increased, hemorrhage and necrosis in the placenta reduced. In TGF-β1 injection group, the expression of pSmad3 and Foxp3 in CD4+ T cells were increased significantly, the expression of CTLA-4 and PD-1 on Tregs and the number of Tregs were also up-regulated. Additionally, the ratio of IL-10/TNF-a was increased at maternal-fetal interface in infected mice with TGF-P injection. The infected pregnant mice with TGF-β1 neutralizing had seriously adverse pregnant outcomes, such as smaller fetuses and placenta, less fetal weight, higher abortion rate, more serious hemorrhaging than those of untreated infected mice. While the expression of pSmad3 and Foxp3 significantly decreased, the number of Tregs obviously reduced, the ratio of IL-10/TNF-α was significantly decreased. The level of pSmad3 correlated positively with the level of Foxp3, CTLA-4, PD-1 or IL-10, while it correlated negatively with the level of TNF-α. In addition, the proliferation molecular Ki-67 has no significant differences in the infected pregnant mice with TGF-β1 neutralizing group or the infected mice with exogenous TGF-β injection compared to the untreated infected mice group.Conclusion:Exogenous injection of TGF-β1 can effectively improve the adverse pregnancy outcomes caused by Toxoplasma infection through TGF-β/Smad3 signaling pathways.