Onion Consumption Modulate Cataract Induced by Sodium Selenite in Rats

Abstract

Onion has been valued for its medicinal qualities by many cultures around the globe. The object of the study is to examine the effect of dietary intake of onion powder on preventing or modulating cataract formation. Antioxidant and apoptotic status in addition to lipids profile and their relation to cataract were also investigated. Twenty six Wister rat pups were divided into four groups. Group 1 (normal control, n=6) received basal diet; group 2 (normal fed on onion, n=6) received basal diet containing 10% onion powder; group 3 (cataract, n=8) received a single subcutaneous (s.c.) injection of sodium selenite (30µmol/kg body weight) and fed on basal diet; and group 4 (cataract , n=6) received a single s.c. injection of sodium selenite and fed on basal diet containing 10% onion powder. Total phenolic compounds of onion were determined. At the end of the experiment (two months) catalase (CAT), superoxide dismutase (SOD) activities, total antioxidant capacity (TAO), reduced glutathione (GSH), malondialdehyde (MDA), nitric oxide (NO) and fas ligand (FAS-L) were assessed in both blood and lens. The levels of lipid profile were determined in rats' serum. Results of slit-lamp examination of both eyes of each rat revealed no lenticular opacification (cataract stage 0) in all eyes of group 1 and 2. Complete lens opacification (stage 4) was noticed in the group 3 (100%), while mild lenticular opacification (cataract stage1) was also noticed in one rat of the group treated with onion (16.7%). The mean activities of the antioxidant enzymes CAT and SOD and levels of TAO and GSH were significantly lower in blood and lenses of cataractous group than normal control or normal fed on onion groups. Conversely, the mean levels of MDA, NO and FAS-L were significantly higher in cataractous rats than normal control or normal fed on onion. In addition, the mean levels of total lipids (TL), triacylglycerols (TG), total cholesterol (TC) and low density lipoprotein-cholesterol (LDL-C) were significantly higher in selenite induced cataract group than in those of normal control and cataract fed on onion rats. In conclusion, the results of this study suggested that consumption of 10% onion powder containing diet can prevent or retard selenite-induced cataract in Wistar rats.