Oxidative Stress and SIRT1-Nrf2 Anti-Ferroptotic Pathways in Granulosa Cells: A Molecular Key to Follicular Atresia and Ovarian Aging

The functional deterioration of granulosa cells (GCs), essential for follicular growth, steroidogenesis, and oocyte competence, indicates ovarian aging and reduced fertility. An expanding corpus of research indicates that oxidative stress is a primary molecular contributor to granulosa cell dysfunction, culminating in mitochondrial impairment, reduced metabolic support for oocytes, and the activation of regulated apoptotic pathways that end in follicular atresia. Ferroptosis, an emergent type of iron-dependent lipid peroxidation, has been identified as a crucial mechanism contributing to chemotherapy-induced ovarian insufficiency, polycystic ovary syndrome (PCOS), and granulosa cell death in aging ovaries, in addition to conventional apoptosis. The SIRT1-Nrf2 axis acts as a crucial anti-oxidative and anti-ferroptotic system that protects GC viability, maintains mitochondrial homeostasis, and upholds redox equilibrium. SIRT1 promotes mitochondrial biogenesis and metabolic resilience by deacetylating downstream proteins, including FOXO3 and PGC-1α. Nrf2 simultaneously controls the transcriptional activation of detoxifying and antioxidant enzymes, including HO-1, SOD2, NQO1, and GPX4, which are critical inhibitors of ferroptosis. Disruption of SIRT1-Nrf2 signalling accelerates GC senescence, follicular depletion, and reproductive aging. In contrast, pharmaceutical and nutraceutical therapies, including metformin, melatonin, resveratrol, and agents that increase NAD+ levels, may reverse ovarian deterioration and reactivate SIRT1-Nrf2 activity. This narrative review highlights innovative treatment prospects for ovarian aging, fertility preservation, and assisted reproduction by synthesising current evidence on ferroptotic pathways, SIRT1-Nrf2 interactions, and oxidative stress in granulosa cells. An understanding of these interrelated biological networks enables the development of tailored therapies that postpone ovarian ageing and enhance reproductive outcomes for women receiving fertility therapy.