nigerloxin and Cataract

The role of osmotic and oxidative stress has been strongly implicated in the pathogenesis of cataract. Nigerloxin, a fungal metabolite, has been shown to possess aldose reductase inhibition and improved antioxidant defense system in lens of diabetic rats. In the present study, the beneficial influence of nigerloxin was investigated in galactose-induced cataract in experimental animals.. Cataract was induced in Wistar rats by feeding 30% galactose in diet. Groups of galactose-fed rats were orally administered with nigerloxin (25 and 100 mg/kg body weight/day) for 24 days.. Lens aldose reductase activity was increased significantly in galactose-fed animals. Lens lipid peroxides and advanced glycation end products were also significantly increased. Antioxidant molecule - reduced glutathione, total thiols and activities of antioxidant enzymes superoxide dismutase and glutathione peroxidase were decreased in the lens of galactose-fed animals. Oral administration of nigerloxin once a day for 24 days at a dose of 100 mg/kg body weight, significantly decreased lens lipid peroxides and advanced glycation end products in galactose-fed rats. Lens aldose reductase activity was reduced and lens antioxidant molecules and antioxidant enzyme activities were elevated significantly by nigerloxin administration.. The results suggest that alteration in polyol pathway and antioxidant defense system were countered by nigerloxin in the lens of galactose-fed animals, suggesting the potential of nigerloxin in ameliorating the development of galactose-induced cataract in experimental animals.

Topics: Aldehyde Reductase; Animals; Antioxidants; Aspergillus niger; Benzoates; Cataract; Diabetes Mellitus, Experimental; Galactose; Glutathione; Lens, Crystalline; Lipid Peroxidation; Male; Oxidative Stress; Polymers; Propane; Rats; Rats, Wistar; Sulfhydryl Compounds; Tryptophan

Osmotic and oxidative stress have been implicated in the pathogenesis of diabetic cataract. Nigerloxin, a fungal metabolite, has been shown to possess aldose reductase inhibitory and free radical scavenging potential, in vitro. In the present study, the beneficial influence of nigerloxin was investigated on diabetes-induced alteration in the eye lens of rats treated with streptozotocin. Groups of diabetic rats were administered nigerloxin orally (100 mg·(kg body mass)(-1)·day(-1)) for 30 days. The activity of lens polyol pathway enzymes (aldose reductase and sorbitol dehydrogenase), lipid peroxides, and advanced glycation end products (AGEs) were increased in the diabetic animals. Levels of glutathione as well as the activity of antioxidant enzymes (superoxide dismutase, glutathione-S-transferase, and glutathione peroxidase) were decreased in the eye lens of the diabetic animals. The administration of nigerloxin significantly decreased levels of lipid peroxides and AGEs in the lens of the diabetic rats. Increase in the activity of aldose reductase and sorbitol dehydrogenase in the lens was countered by nigerloxin treatment. The activity of glutathione and antioxidant enzyme in the lens was significantly elevated in nigerloxin-treated diabetic rats. Examination of the treated rats' eyes indicated that nigerloxin delayed cataractogenesis in the diabetic rats. The results suggest the beneficial countering of polyol pathway enzymes and potentiation of the antioxidant defense system by nigerloxin in diabetic animals, implicating its potential in ameliorating cataracts in diabetics.

Topics: Aldehyde Reductase; Animals; Antioxidants; Benzoates; Cataract; Diabetes Mellitus, Experimental; Free Radical Scavengers; Glutathione; Glycation End Products, Advanced; L-Iditol 2-Dehydrogenase; Lens, Crystalline; Lipid Peroxides; Male; Propane; Rats; Rats, Wistar