[Effects of DL-alpha-lipoic acid on the experimentally induced diabetic cataract in rats].

OBJECTIVE: To investigate whether DL-alpha-lipoic acid (LA) can offer lenticular protection in diabetic rats. METHOD: 36 Brown-Norway (BN) specific pathogen free (SPF) rats (7 week-old, female), were divided into 3 groups comprising of the diabetes mellitus (DM) group (14 rats), the diabetes mellitus treated with LA (DM + LA) group (14 rats), and the control (CTL) group (8 rats). The diabetic cataract was induced by streptozotocin (STZ) injection. Powdered food mixed with 0.3% LA was given to the DM + LA group, 3 days after STZ injection. Lens density was measured with EAS-1000, blood glucose and lens glutathione concentration was examined. RESULT: 2 weeks after STZ injection, there was a subcapsular reticular opacity in the DM; Lens opacity became more severe and enlarged with increased duration of STZ exposure. 4 weeks later, there was slight lens opacity in the DM + LA group. After 5 weeks, there were significant differences in lens densities between the DM and the DM + LA groups (P < 0.01). 3 days after STZ injection, there was no difference between the DM and the DM + LA in blood glucose (P > 0.05); At 80 days, the concentration of blood glucose in the DM + LA was less than that of in the DM (P < 0.01). 10 months after STZ injection, there was no difference of the concentration of glutathione in lens between the DM + LA and the DM (P > 0.05). CONCLUSION: LA ingested orally can effectively reduce STZ-induced blood glucose and inhibit diabetic cataractogenesis in rats.