Oocyte aging in focus: Environmental and endogenous stressors driving reproductive potential decline

Oocyte quality, a critical determinant of female reproductive potential, experiences a progressive decline with age, largely driven by the cumulative effects of oxidative stress and mitochondrial dysfunction. This review thoroughly synthesizes the latest evidence concerning the molecular, cellular, and environmental factors that disrupt redox homeostasis within oocytes. It particularly highlights the pivotal roles of reactive oxygen species, impaired mitochondrial metabolism, epigenetic dysregulation, and alterations in the ovarian microenvironment. We further elucidate how aging, environmental toxicants, lifestyle choices, and pathological conditions such as cystic ovaries and endometriosis exacerbate oxidative damage, thereby severely compromising meiotic competence and embryonic development. Compelling evidence from both human and animal models has shed light on the intricate mechanisms underlying ROS-induced oocyte deterioration, which will be discussed herein. Moreover, we evaluate promising emerging interventions, including antioxidant, dietary, lifestyle, and mitochondria-targeted strategies, all aimed at preserving reproductive longevity. Collectively, these insights firmly establish oxidative stress as a central and undeniable driver of oocyte aging, underscoring the urgent need for integrated biomedical and environmental strategies to safeguard female fertility.