SDF-1 Is Involved In The Initiation Of Preterm And Term Labor By Regulating T-type Calcium Channels In Uterine Smooth Muscle Cells

Objective: Stromal cell derived factor(SDF-1),also a chemokine ligand 12(CXCL12),is a chemokine from the CXC subgroup.This research focuses on the mechanism of labor initiation.By measuring the expression of SDF-1 in the uterine smooth muscle and amniotic fluid of the preterm labor group(PTL),preterm not in labor group(PTNL),term labor group(TL)and term not in labor group(TNL),the differences of SDF-1 among each group and its correlation with preterm labor and labor initiation are analyzed.To explore the regulatory effect of SDF-1 on T-type calcium channels in uterine smooth muscle,in order to clarify the role and preliminary mechanism of SDF-1 in the initiation of preterm and term labor.Methods: In this study,40 patients who received cesarean section in Shengjing Hospital Affiliated to China Medical University from June 2021 to June 2022 were selected,including 10 patients in each group: he preterm labor group(PTL),preterm not in labor group(PTNL),term labor group(TL)and term not in labor group(TNL)The smooth muscle tissue and amniotic fluid of the lower uterine segment of the four groups of patients were collected,and the expression of SDF-1 in the smooth muscle tissue and amniotic fluid of the four groups of patients was detected by immunohistochemistry,Western-blot,q PCR and ELISA,and the correlation between the expression of SDF-1 and the initiation of labor was analyzed.Uterine smooth muscle cells were selected for primary culture and given recombinant SDF-1 and AMD3100(CXCR4 antagonist of SDF-1 receptor)for intervention.Western-blot and q PCR were used to detect the expression of T-type calcium channels.The protein expression level of NF-κB was detected by Western blot.Results: The expression of SDF-1 was increased in preterm delivery and labor initiation groups.Immunohistochemical results showed that the expression of SDF-1 was lower in PTNL and TNL,but higher in PTL and TL,and the difference was statistically significant(P<0.05).Western-Blot assay results showed that the protein expression levels of PTNL and TNL were lower than those of PTL and TL,and the difference was statistically significant(P<0.001).q PCR detection results showed that m RNA expression levels in the PTNL and TNL groups were lower than those in the PTL and TL groups,and the difference was statistically significant(P<0.05).In amniotic fluid,the expression of SDF-1 was higher in the PTL and TL groups,but lower in the PTNL and TNL groups,and the difference was statistically significant(P<0.0001).q PCR and Western blot were used to detect the effects of recombinant SDF-1 and its receptor antagonist AMD3100 on the m RNA and protein expression levels of T-type calcium channels after intervention in primary cells.The results showed that the expression levels of T-type calcium channels were decreased(P<0.05).After the intervention of recombinant SDF-1,the expression of NF-κB increased,and after the intervention of recombinant SDF-1 and AMD3100,the expression of NF-κB decreased(P<0.05).Conclusion: Increased SDF-1 expression is closely related to preterm delivery and term delivery initiation.SDF-1 maybe involved in the initiation of labor and the occurrence of preterm labor by regulating T-type calcium channels in uterine smooth muscle.