[The oxidative stress in the cataract formation]

Area of Science:

• Ophthalmology
• Biochemistry
• Gerontology

Context:

• The eye lens is an avascular tissue susceptible to oxidative damage.
• Aging and diabetes mellitus are known risk factors for cataract development.
• Peroxidative reactions play a crucial role in the pathogenesis of cataracts.

Purpose:

• To investigate the role of peroxidative reactions in cataract formation.
• To examine changes within lens tissues and the surrounding ocular environment.
• To compare oxidative stress markers in senile and diabetic cataracts.

Summary:

• Superoxide dismutase (SOD) activity decreases and lipid peroxide levels increase with age in rat and mouse lenses.
• Free radicals, including hydroxyl (HO.) and ascorbic acid radicals, are generated within cataractous lenses.
• Diabetic cataracts show higher levels of glucose, glycated protein, and lipid peroxide compared to senile cataracts, with nuclear types exhibiting the greatest peroxide accumulation.
• Transitional metals like copper accumulate in the lens, potentially increasing peroxidation.
• Lens membrane integrity is compromised in cataracts, evidenced by altered phospholipid and fatty acid composition and increased lipoprotein incorporation.
• The ocular environment in diabetic patients exhibits reduced antioxidant capacity and increased oxidative stress markers.
• In vitro studies confirm that reduced antioxidant protection and high glucose levels exacerbate lipid peroxidation and decrease SOD activity in cultured lenses.

Impact:

• Findings highlight the significant contribution of oxidative stress and peroxidative damage to cataractogenesis.
• Understanding these mechanisms may lead to novel therapeutic strategies for preventing or treating cataracts.
• The study underscores the importance of managing oxidative stress in both aging populations and diabetic patients to preserve lens health.