Monosodium Glutamate Effect on The Expression of ɑ7nACHR and ɑ4nACHR Subunits in The Testicular Tissue.

Background: Monosodium glutamate (MSG) is a popular food flavor enhancer, and a glutamate subset that induces different toxicities such as hepatotoxicity, neurotoxicity, reproductive toxicity, and nephrotoxicity. This study was conducted to assess the effects of MSG on the α7 and α4 nicotinic acetylcholine receptor (nACHR) protein subunits expression of adult rat testis and the safety role of vitamin C.

Materials and methods: For this experimental research, 24 rats were haphazardly grouped into four equal groups (n=6) and orally gavaged for 30 days as follows: control group (distilled water gavage), MSG group (3 g/kg/b.w/ day), vitamin C group (150 mg/kg/b.w/day), and MSG+vitamin C group (3 g/kg/b.w/day+150 mg/kg/b.w/day, respectively) that rats of all groups on the 30^th day were anesthetized, and the left testes were used for of α4 and α7 nACHR protein subunit evaluation by immunohistochemistry (IHC). Statistical computations were performed using Graph Pad Prism software.

Results: The present study revealed a significant reduction in the expression and optical density (OD) of α7 nACHR and α4 nACHR in the seminiferous tubules and intertubular connective tissue in the MSG group compared to the control group. In the MSG+vitamin C group, the expression and OD of α7 nACHR and α4 nACHR increased in the seminiferous tubules and intertubular connective tissue but this improvement was not significant compared to the MSG group.

Conclusion: MSG decreased the expression level of nACHR protein subunits, α7 and α4, in the seminiferous tubules and interstitial testicular tissue. Vitamin C in the MSG+vitamin C group could not significantly improve the expression of α7 and α4 nACHR subunits in testicular tissue. Probably, MSG toxicity can be compensated with higher doses of vitamin C.