Research progress on multi-mechanism analysis and protection strategies of ovarian aging and fertility decline.

Age-related fertility decline is an increasingly important challenge in reproductive medicine, driven largely by progressive ovarian aging. The aging ovary undergoes functional deterioration characterized by reduced ovarian reserve and declining oocyte quality, ultimately limiting female reproductive lifespan. Although multiple molecular and cellular processes associated with ovarian aging have been identified, these mechanisms are often discussed independently, limiting an integrated understanding of how they interact within the ovary. In this review, we propose an ovary-centered, multi-mechanistic framework to organize current evidence on ovarian aging and fertility decline. We discuss how genomic instability, telomere attrition, mitochondrial dysfunction, oxidative stress, chronic cellular stress responses, and alterations in ovarian signaling and microenvironmental homeostasis collectively contribute to follicle depletion and impaired oocyte competence. Particular emphasis is placed on signaling pathways involved in follicle activation and stress adaptation, including PI3K/AKT/mTOR, FOXO3, Hippo, and AMPK-Sirtuin networks, while acknowledging that many mechanistic relationships remain incompletely defined in physiological ovarian aging. Building on this integrative perspective, we further evaluate mechanism-oriented intervention strategies, including mitigation of cellular stress, metabolic and signaling modulation, optimization of the ovarian microenvironment, established fertility preservation technologies, and emerging exploratory approaches. By integrating current mechanistic and translational evidence, this review provides a conceptual framework for understanding ovarian aging and highlights future directions for evidence-based fertility preservation and reproductive health management in the context of aging.