Histological and epigenetic alterations in vaginal relaxation syndrome: evidence from m6A-Seq, RNA-Seq, and animal models.

Abstract

BACKGROUND: Vaginal relaxation syndrome (VRS) is characterized by weakening of the vaginal wall due to childbirth, aging, or pelvic floor injury. The molecular and histological mechanisms underlying VRS remain poorly understood. This study aimed to investigate the morphological and epigenetic changes associated with VRS by integrating histological evaluation with transcriptomic and epitranscriptomic profiling. MATERIALS AND METHODS: Vaginal tissue samples from patients with VRS and healthy controls were analyzed using m6A MeRIP-seq and RNA-seq to identify joint differential genes. Functional enrichment and protein-protein interaction (PPI) analyses were performed. Validation was carried out in peripheral blood samples and in a rat VRS model using real-time reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blot. Histological changes were assessed with hematoxylin-eosin (H&E) and Masson's trichrome staining. RESULTS: Twenty-two genes exhibited concurrent changes in both m6A methylation and expression, enriched in pathways including MAPK, NF-κB, and C-type lectin receptor signaling. Histological analysis revealed decreased mucosal thickness and collagen fiber density in VRS tissues and in the rat model, consistent with molecular alterations. Key regulators such as TNF-α, NFATC1, and DUSP8 were confirmed at mRNA and protein levels. CONCLUSIONS: This integrated approach highlights that VRS involves not only molecular dysregulation but also distinct histological remodeling. Our findings provide novel insights into the pathogenesis of VRS and suggest potential diagnostic markers and therapeutic targets linking epigenetic regulation with morphological alterations.