Histochemical Studies of the Effects of Monosodium Glutamate on the Liver of Adult Wistar Rats

BACKGROUND Monosodium glutamate (MSG) is a commonly used food additive and there is growing concern that excitotoxins such as MSG play a critical role in the development of several hepatic disorders. OBJECTIVES The histochemical effect of monosodium glutamate was investigated on the liver of adult Wistar rats. METHODS Adult male Wistar rats (n = 24), with an average weight of 230 g were randomly assigned into two treatment groups, (A & B) (n=16) and Control (C) (n=8). The rats in the treatment groups (A & B) received 0.04mg/kg and 0.08mg/kg of monosodium glutamate thoroughly mixed with the grower's mash, respectively on a daily basis for forty-two days. The 0.04mg/kg and 0.08mg/kg monosodium glutamate doses were chosen and extrapolated in this experiment based on the previous work done with the additive. The control group (C) received equal amount of feed (Growers' mash) without monosodium glutamate added for the same period. The rats were given water ad libitum. Both the treatment and control rats were sacrificed by cervical dislocation on day forty-three of the experiment. The Liver was carefully dissected out and quickly fixed in Bouin's fluid for histochemical studies, while blood was collected for estimation of total protein, albumin, transaminasese (aspartate aminotransferase (AST) and alanine aminotransferase (ALT). RESULTS The histological findings showed changes like dilatation of the central vein, which contained lysed red blood cells, cyto-architectural distortions of the hepatocytes, atrophic and degenerative changes on the liver of the animals that received feed incoporated with monosodium glutamate. Furthermore, the biochemical parameters were significantly higher in the test than control groups (P < 0.0001). These changes were more severe in the group that had 0.08 mg/kg of monosodium glutamate mixed in their feed. CONCLUSION These findings showed that monosodium glutamate consumption may have some deleterious effects on the liver of adult Wistar rats at higher doses and by extension may affect the functions of the liver.