Objective To explore the mechanism of methyltransferase METTL3 in premature ovarian failure(POF)using a POF mouse model,providing a theoretical basis for the pathological research and clinical treatment of POF.Methods C57BL/6 female mice aged 6 to 8 weeks were selected for the study.The experimental group consisted of mice with a premature ovarian failure(POF)model established using the D-galactose metabolic method,while the control group comprised normal mice subjected to the same intervention with an equal volume of physiological saline.The levels of sex hormones were measured using ELISA,and histopathological changes in ovarian tissue were observed through HE staining to verify the successful establishment of the POF mouse model and to explore the correlation between METTL3 and POF at the tissue level.Additionally,stable transgenic mouse granulosa cell lines with METTL3 overexpression and knockdown were constructed at the cellular level.Cell proliferation and apoptosis were assessed using CCK-8 and FITC/PI dual staining methods to clarify the regulatory role of METTL3 in granulosa cell apoptosis and its impact on the occurrence of POF.Results The POF mouse model was successfully established.TUNEL staining revealed a significant increase in apoptotic granulosa cells in the ovarian tissue of the POF group(P＜0.05),which also exhibited high expression of METTL3.In cellular experiments,stable transcriptional cell lines of mouse granulosa cells with METTL3 overexpression and knockdown were successfully constructed.Upregulation of METTL3 expression promoted granulosa cell apoptosis and inhibited their proliferation(P＜0.05).Conclusion METTL3 participates in the development of POF by promoting granulosa cell apoptosis.