[Free radicals on cataracts induced by sodium selenite studied by ESR and LPO]

We made a electron spin resonance (ESR) study on rat cataracts induced by Na2SeO3. A signal was detected at about g = 2.0026, and the content of electron spins (CES) in lens of rat administrated Na2SeO3 for a short time is higher than that of control significantly. At the late stage of cataracts, the content of CES was lower than normal level. The results of kinetics analysis showed that the CES grow up with the administration of Na2SeO3 and decays in index-law after administration. The results suggested that free radical scavengers or antioxidants should be useful for preventing cataracts at initial stage of the oxidation damage to lens, but they could aggravate cataracts at late stage of cataracts. This can explain the controversy about the curative effect of antioxidant to cataracts.