The role of cervical microbiome in cervical incompetence: insights from 16 S rRNA metagenomic sequencing.

Cervical incompetence (CI) is recognized as a critical factor contributing to mid-pregnancy miscarriage and preterm delivery, significantly affecting pregnancy outcomes. Despite this, the specific role of the microbiome in this pathological process remains inadequately understood. This study seeks to elucidate the core microbiome associated with CI in pregnant women and explore its potential biological mechanisms. Utilizing 16 S rRNA metagenomic sequencing, we examined the cervical mucus microbiota of women with CI both pre-operatively (PreOp) and post-operatively (PostOp). Subsequently, the immunomodulatory effects of these microbial communities on the immune system were systematically assessed using quantitative real-time PCR, Western blotting, and enzyme-linked immunosorbent assay. The findings revealed a significant reduction in microbial diversity and richness in PostOp cervical mucus, alongside notable alterations in microbiota composition. The genera Lactobacillus, Bifidobacterium, Gardnerella, Streptococcus, and Anaerococcus were identified as predominant. Further analysis demonstrated that treatment with 25% Lactobacillus crispatus (L. crispatus) supernatants, in comparison to 25% Group B Streptococcus (GBS) supernatants, resulted in high cell viability and normal morphology in HcerEpic cells. Importantly, the combination of 25% L. crispatus and 25% GBS supernatants significantly reduced the mRNA and protein expression levels of Toll-like receptor 4 (TLR4), Toll-like receptor 2 (TLR2), and nuclear factor kappa B (NF-κB) in vitro. These results indicate that L. crispatus may play a role in modulating cervical inflammation in CI by suppressing the TLR/NF-κB signaling pathway, potentially contributing to a more stable cervical microenvironment during pregnancy.