Study on the mechanism of preterm birth caused by changes in maternal microflora based on maternal fetal immune imbalance
基于母胎免疫失衡的孕母菌群改变所致早产的机制研究

摘要

目的 本研究旨在探讨母胎免疫失衡下孕母阴道菌群改变与早产的关系。方法 纳入2021年1月至2021年12月在我院产科住院的早产孕妇（孕周<37周）30名和足月产孕妇（孕周≥37周）30名，并于其分娩前采集阴道拭子，提取微生物DNA，并进行16S rRNA测序，采用Shannon指数、OTU数量和Faith's PD指数分别评估菌群多样性、丰富度和演化多样性。胎盘免疫组织化学染色观察FoxP3蛋白表达分布，并计算其平均累计光密度值，以了解Treg细胞分布情况。结果 早产孕妇组的Shannon指数（2.35±0.43）低于足月孕妇组（3.12±0.50），P<0.05，早产孕妇组的平均OTU数量（432.11±58.22）低于足月孕妇组（509.12±65.32），P<0.05；早产孕妇组的Faith's PD指数（15.71±3.41）低于足月孕妇组（18.92±4.22），P<0.05。与足月胎盘组（0.201±0.13）相比，早产胎盘组（0.168±0.12）具有较低的FoxP3蛋白平均累计光密度值。结论 早产孕妇阴道菌群多样性、丰富度和演化多样性均降低，可能通过改变Treg细胞分布来影响妊娠维持，从而导致早产。

Abstract

Objective The purpose of this study was to investigate the relationship between the changes of vaginal flora and preterm labor in pregnant women with imbalanced maternal fetal immunity. How: Thirty preterm pregnant women (<37 weeks gestation) and 30 full-term pregnant women (≥37 weeks gestation) admitted to the obstetrics Department of our hospital from January 2021 to December 2021 were included. Vaginal swabs were collected before delivery, microbial DNA was extracted, and 16S rRNA sequencing was performed. Shannon index, OTU number and Faith's PD index were used to evaluate microbial diversity, richness and evolutionary diversity, respectively. The distribution of FoxP3 protein was observed by immunohistochemical staining of placenta, and its average cumulative optical density was calculated to understand the distribution of Treg cells.
Results: The Shannon index (2.35±0.43) in the preterm pregnant women group was lower than that in the full-term pregnant women group (3.12±0.50), P<0.05. The mean OTU number in the preterm pregnant women group (432.11±58.22) was lower than that in the full-term pregnant women group (509.12±65.32), P<0.05. The Faith's PD index of preterm pregnant women (15.71±3.41) was lower than that of full-term pregnant women (18.92±4.22), P<0.05. Compared with the full-term placenta group (0.201±0.13), the preterm placenta group (0.168±0.12) had a lower average cumulative optical density of FoxP3 protein.
Conclusion  : The diversity, richness and evolutionary diversity of vaginal flora in preterm pregnant women are decreased, which may affect the maintenance of pregnancy by changing the distribution of Treg cells, thus leading to preterm birth.