Suppression of Monosodium Glutamate-Induced Acute Kidney Injury and Renal Ultrastructural Damage in Rats by Vitamin E

Abstract

Food additives and flavour enhancers used in the food industry are potential health risks. We tested the hypothesis that the food additive and flavour enhancer, monosodium glutamate (MSG), which is the sodium salt of glutamic acid can induce ultrastructural alterations to the kidney, and the antioxidant vitamin E can protect against acute kidney injuries induced by a toxic dose of MSG in a rat model of the disease. The model group of rats received a daily dose of MSG (4 gm/kg) for 7 days, whereas the protective groups were either received a 100 mg/kg vitamin E plus MSG or 300 mg/kg vitamin E plus MSG for 7 days. Rats were then sacrificed on day 8. Transmission and light microscopy images revealed substantial kidney damage induced by MSG in the model group as demonstrated by degenerated epithelial cells with Pyknotic nuclei, swollen mitochondria, damaged brush margins, dilated tubules, and widening of Bowman's space with shrinkage and deformity of some glomeruli. Treatment of the model group with vitamin E showed a substantial protection of kidney tissue and renal ultrastructure by 300 mg/kg vitamin E compared to a partial protection by 100 mg/kg vitamin E. In addition, MSG significantly (p<0.05) increased serum levels of urea and creatinine, which were significantly (p<0.05) decreased with vitamin E. However, for serum creatinine, high doses of vitamin E (300 mg/kg) were more effective than lower doses (100 mg/kg) of vitamin E. These results indicate that vitamin E at 300 mg/kg effectively protects against MSG-induced acute kidney injury in rats.