INVESTIGATING OXIDATIVE STRESS - INDUCED APOPTOSIS IN AGE RELATED MACULAR DEGENERATION

Abstract

Age-related macular degeneration (AMD) is a leading cause of central vision loss in the elderly, characterized by progressive degeneration of the retinal pigment epithelium (RPE). Oxidative stress has been implicated as a major contributor to AMD pathogenesis, yet the mechanistic relationship between oxidative injury, mitochondrial dysfunction, and apoptosis remains incompletely understood.
This study aimed to investigate the role of oxidative stress-induced apoptosis in AMD by integrating experimental, clinical, molecular, and expert-level qualitative data. A mixed-method approach was adopted. Human RPE cells were exposed to increasing concentrations of hydrogen peroxide (H₂O₂) to simulate oxidative stress, and apoptotic markers were quantified using caspase-3 activity assays and JC-1 fluorescence for mitochondrial membrane potential. Clinical data were collected from AMD patients (n=100) and age-matched controls (n=50) to measure oxidative biomarkers (MDA, 8-OHdG) and antioxidant enzymes (SOD, catalase). Gene expression analysis of apoptosis-related genes (BAX, BCL-2, CASP3, CYCS, TP53) was performed, and expert interviews with ophthalmologists provided clinical perspectives. Caspase-3 activity increased significantly with rising H₂O₂ exposure, accompanied by a marked decline in JC-1 red/green fluorescence, confirming apoptosis and mitochondrial dysfunction. Clinical biomarker analysis revealed that AMD patients had significantly higher levels of MDA (6.57 nmol/mL) and 8-OHdG (5.41 ng/mL), with reduced SOD and catalase activity (p < 0.01). Strong correlations were observed between oxidative stress markers and AMD severity (r = 0.81 for MDA, r = -0.69 for catalase). Gene expression analysis showed upregulation of pro-apoptotic genes and downregulation of BCL-2. Expert interviews corroborated the mechanistic findings and highlighted current diagnostic and therapeutic gaps. Oxidative stress plays a pivotal role in AMD progression by inducing mitochondrial dysfunction and apoptosis in RPE cells. These findings suggest that oxidative biomarkers and apoptotic regulators may serve as valuable tools for early diagnosis and targeted therapy in AMD management.