A Histological Study of the Hepatic and Renal Effects of Subchronic Low Dose Oral Monosodium Glutamate in Swiss Albino Mice

Aim: Earlier studies have shown that exposure to monosodium glutamate (MSG) in large doses during the neonatal period may result in steatohepatitis and evidence of pre-neoplastic changes in the liver. However, the effect of low dose, chronic oral MSG intake on the histology of the liver and kidneys have not been addressed to date, this study was designed to ascertain if MSG consumption at these doses is associated with histological evidence of hepatic or renal injuries.
Study Design: Experimental study.
Place and Duration of Study: Department of Anatomy and Department of Pharmacology Ladoke Akintola University of Technology Ogbomosho Oyo State Nigeria between October and November 2011.
Methodology: Forty adult male Swiss albino mice weighing between 20-25 mg were assigned into 4 groups A, B, C and D of ten mice each (n=10). Group A served as control and received normal saline while groups B, C and D received MSG daily at 0.5, 1.0 and 1.5 mg MSG /kg body weight (BW) dissolved in normal saline respectively for 28 days. On day 29 of the study animals were sacrificed, and the liver and kidneys were removed, weighed and processed for histological examination. Statistical analysis was by one way ANOVA followed by a posthoc test, and results were expressed as mean ±S.E.M.
Results: MSG consumption resulted in a significant increase in the relative liver weight at 1.0 and 1.5 mg MSG /Kg BW and a relative increase in kidney weight occurring at 1.5 mg/Kg BW (P<0.05). This was accompanied by a dose- dependent increase in body weight compared to control which failed to reach statistical significance. Liver and kidney histology indicated a loss of normal liver architecture with varying degrees of disorganization and apoptotic cell death compared to controls. The kidneys of MSG-exposed mice exhibited contraction of the renal glomerulus and thickening of the walls of the renal tubules.
Conclusion: The study provides evidence that oral consumption of MSG at doses within the Acceptable Daily Intake (ADI) may promote hepatic and renal injuries.