P-648 The Role of THBS2 in Ovarian Function and Its Potential Mechanism in Primary Ovarian Insufficiency

Abstract Study question What is the role of THBS2 in ovarian function, and what is its potential mechanism in primary ovarian insufficiency (POI)? Summary answer THBS2 knockout mice demonstrate decreased fertility and ovarian dysfunction, accompanied by the downregulation of FMOD, a critical regulator of the TGF-β signaling pathway. What is known already Primary Ovarian Insufficiency (POI) is characterized by amenorrhea, infertility, and elevated follicle-stimulating hormone (FSH) levels before the age of 40. The pathogenesis of POI remains largely unclear, limiting the effectiveness of current treatments. Preliminary studies have suggested a role for THBS2 in ovarian dysfunction. Study design, size, duration This research was conducted using a controlled experimental design involving THBS2 knockout and wild-type mice. The study spanned two years and included multiple cohorts of mice for fertility and gene expression analysis. Participants/materials, setting, methods We used THBS2 gene knockout (KO) mice and wild-type (WT) controls. Ovarian function was assessed through fertility tests, hormone level measurements, and histological analysis. Oocyte maturation was evaluated using in vitro maturation (IVM) assays. Gene expression profiles were analyzed using RNA sequencing (RNA-seq) and confirmed by qPCR and immunofluorescence. Main results and the role of chance The THBS2 knockout mice demonstrated markedly reduced fertility, evidenced by a decreased number of pups per litter (4.3±1.4 compared to 8.6±1.3, P < 0.01) and prolonged estrous cycles. Hormonal analysis revealed elevated serum levels of FSH (P < 0.05) and LH (P < 0.05), coupled with decreased E2 levels (P < 0.05), indicating ovarian dysfunction. Oocyte maturation was adversely affected, as reflected by diminished fertilization rates and increased degeneration. Differential gene expression analysis identified the downregulation of FMOD, a critical regulator of the TGF-β signaling pathway, which was corroborated by qPCR and immunofluorescence techniques. These findings were consistently observed across multiple experimental iterations, reducing the likelihood of random variation.The findings of this study underscore the pivotal role of THBS2 in ovarian function and oocyte maturation. The downregulation of FMOD in THBS2 knockout mice provides insight into a potential mechanistic pathway through which THBS2 influences these processes. Limitations, reasons for caution The study’s reliance on animal models poses a limitation, as these models may not fully replicate the pathophysiology of human premature ovarian insufficiency (POI). Consequently, further validation in human subjects is warranted. Wider implications of the findings Elucidating the role of THBS2 in ovarian function may unveil novel therapeutic targets for POI, potentially enhancing fertility outcomes and mitigating associated health risks. Trial registration number No