Expression Of Tim-3 And Gal-9 In Maternal Fetal Interface And Its Correlation With Spontaneous Preterm Birth

Objective: To investigate the high-risk factors of spontaneous preterm birth,the expression of Tim-3 and Gal-9 in maternal-fetal interface and their relationship with spontaneous preterm birth.Materials and methods: From September 2018 to September 2020,according to the diagnostic criteria of SPB,64 cases of pregnant women with preterm birth(spontaneous premature birth group A)and 100 cases of pregnant women with normal full-term delivery(control group A)were selected.Decidua,fetal membrane and peripheral blood were collected from 30 cases of spontaneous preterm birth and 30 cases of normal delivery respectively as spontaneous preterm birth group B and control group B.Western blot(WB)and immunohistochemistry(IHC)were used to detect the expression levels of Tim-3 and Gal-9 in decidua and fetal membranes.The levels of IFN-γ,IL-10 and IL-17 in venous blood were determined by double antibody sandwich enzyme-linked immunosorbent assay.Using spss19.0 statistical software to analyze the data,we explored the risk factors of spontaneous preterm birth,and studied whether Tim-3 and Gal-9 were associated with spontaneous preterm birth.Result:1.There were significant differences in pregnancy times,the gestational age at which the examinations begin,the gestational age of delivery,times of prenatal examination and educational level between preterm group A and normal group A(P<0.01).There was no significant difference in other indicators,such as maternal age,pre pregnancy BMI and growth BMI between the two groups.2.There were significant differences in the cleanliness of leucorrhea(P<0.01),positive rate of bacterial culture(P < 0.05),CRP(P < 0.05),prenatal leukocyte count and neutrophil count(P<0.01)between spontaneous preterm labor group A and normal group A.3.There was no significant difference in the outcome of pregnant women between spontaneous preterm birth group A and normal group A from chorioamnionitis,postpartum hemorrhage,puerperal infection and urinary retention.4.There were significant differences in neonatal weight,neonatal Apgar score and neonatal respiratory distress between spontaneous premature birth group A and normal group A(P < 0.01),but there was no significant difference in the incidence of neonatal asphyxia.5.In the decidua and the fetal membrane,Tim-3 protein mainly expressed in cell membrane and cytoplasm,while Gal-9 mainly expressed in cytoplasm.The average optical density of the positive signals in the two groups was measured and statistically analyzed.The results showed that the expressions of Tim-3 and Gal-9 in decidua of premature group B were significantly lower than those of normal group B(P<0.05).The expression of Tim-3 in decidua of preterm group B was 0.890 times of that of normal group,while the expression of Gal-9 in decidua of preterm group B was 0.936 times of that of normal group.The results showed that the expression of Tim-3 and Gal-9 in the embryolemma of preterm group B was significantly lower than that of normal group B(P<0.05).The expression of Tim-3 in the embryolemma of preterm group B was 0.891 times of that in normal group B.The expression of Gal-9 in the embryolemma of preterm group B was 0.914 times of that of normal group B.6.Western blot showed that the protein levels of Tim-3 and Gal-9 in decidua of spontaneous preterm group B were significantly lower than those of normal group B(P <0.05;P < 0.05).The protein levels of Tim-3 and Gal-9 in fetal membranes of spontaneous preterm group B were also significantly lower than those of normal group B(P < 0.05;P< 0.05).The expression of Tim-3 in decidua of preterm group B was 0.371 times that of normal group B.The expression of Gal-9 in decidua of preterm group B was 0.394 times that of normal group B.The expression of Tim-3 in fetal membranes of preterm group B was 0.187 times higher than that in normal group B.The expression of Gal-9 in fetal membranes of preterm group B was 0.785 times higher than that in normal group B.7.Considering that Tim-3 interacts with Gal-9 and down regulates Th1 immune response,we detected the expression of Th1 and Th2 cytokines in peripheral blood of preterm group B and normal group B.IFN-γ is used to represent Th1 type cytokines,IL-17 is used to represent Th17 type cytokines,and IL-10 stands for Th2 type cytokines.The results showed that the concentration of IFN-γ in preterm group B was significantly higher than that in normal group B(P < 0.01).In addition,the concentration of IL-17 in preterm group B was also higher than that in normal group B(P < 0.05),while the concentration of IL-10 in preterm group B was significantly lower than that in normal group B(P < 0.05).Conclusions1.Pregnant women with history of abortion or preterm birth,low education level,examinations starting late and less times of prenatal examination are more likely to have spontaneous preterm birth.The gestational age of spontaneous preterm birth group is significantly lower than that of normal group.2.The risk of infection in spontaneous premature delivery group is higher than that in normal group.3.Low birth weight,low Apgar score and poor prognosis of spontaneous preterm infants.4.Compared with the normal group,the expression of Tim-3 and Gal-9 in decidua and fetal membranes of preterm group was down regulated.With the increase of IFN-γ and IL-17 levels,the Th1 and Th17 responses of spontaneous preterm delivery women increased significantly,and the ability of Th2 cells to secrete IL-10 decreased sharply.Spontaneous preterm birth may be related to the down-regulation of Tim-3 and Gal-9 at the maternal fetal interface.We speculate that Tim-3-Gal-9 pathway may regulate the immune microenvironment of maternal fetal interface and maintain immune tolerance by transforming Th1 dominance into Th2 dominance.