Sensitivity of Redox Cycle Enzymes in Substantiating the Pathophysiology of Cataract

Oxidative modifications play major role in the formation of cataract. Lens contains several protective mechanisms against oxidizing agents viz. catalase, superoxide dismutase, glutathione reductase, glutathione peroxidase, and ascorbic acid. To explore the oxidative damage that might be occurring with 'Invitro' development of cataracts induced by sugars, H 2 O 2 and steroids. We examined redox status of cataractous lenses by analysing enzymatic defence meachanisms. Lenses were exposed to glucose (50 mM) (Group – I); galactose (35 mM) (Group – II) and xylose (30 mM) (Group – III) and maintained at 37°C for 72 hours so as to induce sugar cataract. H 2 O 2 cataract was produced by adding 50 mM (Group – IV) and 100 mM (Group – V), solution to culture media (AAH). Steroid cataract was generated by adding a freshly prepared l x 10 -4 M dexamethasone (mw 392.5) (Group – VI) in absolute alcohol to the culture media (AAH) and incubated at 37°C for 72 hours. Subsequent to the development of the cataract, the lenses were homogenized and the specific activity of the enzymes catalase (CAT), glutathione peroxidase and glutathione reductase was assessed. Catalase activity did not show any significant decrease in sugar cataract and steroid cataract but a significant decrease was observed in H 2 O 2 cataract. However a significant decrease in GSH-Px and GSH-Rx were found in all the three types of experimental cataract as compared to control lenses.