ROLE OF LIPID-PEROXIDATION IN THE PATHOGENESIS OF MYOPIC AND SENILE CATARACT

Aims/background - Increased production of free radicals, consumption o f antioxidant, and oxidation of unsaturated lipids have been observed recently in cataractous lenses and active participation of the retina in human cataractogenesis has been proposed. To verify this hypothesis , the total (GSH) and oxidised (GSSG) glutathione concentrations were assayed in the lens and the malondialdehyde (MDA) levels assayed in th e vitreous and in the lens of normal controls and patients with senile or myopic cataract. Methods - The study was conducted on 34 lenses (n ucleus and epinucleus) (nine clear lenses, 14 lenses with idiopathic s enile cataract, and 11 lenses affected by severe myopic cataract) and vitreous of 19 (seven non-myopic, seven myopic, and five control) subj ects. Glutathione determination was performed following the method of Reed, while malondialdehyde was assayed using a modification of the me thod of Dahle. Results - Cataractous lenses showed a decreased content of GSH and increased concentration of GSSG compared with clear lenses . A higher oxidative consumption of GSH was found in myopic cataracts compared with senile ones. Also, increased levels of MDA were observed both in cataractous lenses and in the vitreous of myopic patients com pared with the control and the senile ones. Conclusion - The observed alterations strongly suggest that retinal lipid peroxidation might pla y a key role in human cataractogenesis, especially in the myopic type.