Histopathological Evaluation of Organs of Male Wistar Rats Fed with Monosodium Glutamate Treated-diet

Background: Recently, the use of seasonings to enhance the flavour of food has increased. A variety of seasonings are produced nowadays and the constituents of these flavour-enhancers are unknown to ignorant consumers. Most consumers preferred to eat food with good taste without considering the effect of additives on their health. One of the most commonly used food additives is monosodium glutamate that is widely used as a food seasoning.

Aim: This study sought to evaluate the histopathological changes in Wistar rats fed with monosodium glutamate treated-diet.

Place: This research was carried out at the Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, Abia State University, Uturu, Nigeria in 2011.

Methods: MSG (3 g/sachet containing 99% MSG) was obtained from a Grocery Store at New Market, Aba in Abia State, Nigeria. 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. The 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, 1,000 mg/kg and 1,250 mg/kg 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 humanely sacrificed and organs were harvested.

Result: The LD50 was taken to be 500 mg/kg, which is the median of 200 mg/kg which did not kill any of the animals and 800 mg/kg that killed all its animals. The histopathology of the testes, liver, spleen, heart, lungs and kidneys were evaluated. Treatment with MSG was observed to cause necrosis in the organs investigated.

Conclusion: The results of this study showed that MSG is toxic to organs of the animals used and its use as flavour enhancer should be discouraged.