Nephrotoxicity of Monosodium Glutamate (MSG) in Wistar Rats

Background: Nowadays, monosodium glutamate (MSG) is frequently used as a flavour enhancer, the fact of which makes it one of the most applied food additives in modern nutrition all over the world. But accurate information on the daily intake of specific food additives by individuals is difficult to obtain especially for food additives that are considered to be safe.

Aim: This study sought to investigate the nephrotoxic effect of MSG on Wistar rats.

Methods: Forty Wistar rats were used for this study. Fifteen of the rats were used for acute toxicity test (LD50) and twenty-five for the experiment. Twenty-five (25) Wistar rats were divided into five groups of 5 rats each. Animals in groups A, B, C, and D were respectively administered 500 mg/kg, 750 mg/kg, 1000 mg/kg and 1,250 mg/kg b. w. of MSG thoroughly mixed with standard feed for eight weeks. Animals in group E received an equal amount of feeds without MSG added. This group served as the control group. At the end of 8 weeks, animals were fasted overnight and sacrificed under diethyl ether anaesthesia. Renal indices were determined using standard methods.

Results: The LD50 was taken to be 500 mg/kg b. w., which is the median of 200 mg/kg b. w. which did not kill any of the animals and 800 mg/kg b. w. that killed all its animals. MSG was observed to increase the concentrations of creatinine, urea, total bilirubin, conjugated bilirubin and unconjugated bilirubin.

Conclusion: The elevation of renal indices by MSG is an indication that it is nephrotoxic.