Food additives such as nitrates and nitrites, and monosodium glutamate (MSG) used in the food industry increase the risk of certain cancers and inflict damage to vital organs. We sought to determine whether the antioxidant vitamin E can protect against liver injuries induced by a toxic dose of MSG in a rat model of MSG-induced acute liver injury. 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 at day 8. Transmission and light microscopy images revealed substantial liver tissue damage induced by MSG in the model group as demonstrated by apoptotic hepatocytes with Pyknotic nuclei and irregular nuclear membrane, and cytoplasm displayed many vacuoles, swollen mitochondria, dilated endoplasmic reticulum, dilated blood sinusoids and bundles of collagen fibers in extracellular space. Treatment of the model group with vitamin E showed a substantial protection of liver tissue and hepatocellular architecture by 300 mg/kg vitamin E compared to a partial protection by 100 mg/kg vitamin E. In addition, MSG significantly (p < .05) modulated serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), superoxide dismutase (SOD), and glutathione peroxidase (GPx), which were significantly (p < .05) protected with vitamin E. Thus, vitamin E at 300 mg/kg effectively protects against MSG-induced acute liver injury in rats, possibly via the inhibition of inflammation, and up-regulation of endogenous antioxidants.
Keywords: Hepatocyte ultrastructure; animal model; inflammation; monosodium glutamate; vitamin E.