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Objective
This study aimed to assess the effect of chronic administration of Monosodium Glutamate (MSG) on blood cells, thymus, spleen, and inflammatory indicators through interleukin (IL)-17 and interleukin (IL)-10 gene expression levels in blood and in thymic and spleen tissues in male Wistar rats.
Methods
Rats were treated with MSG orally once daily for 90 days at two different doses with and without probiotic supplementation (Bacillus Subtilis and Bacillus Pumilus). Blood samples were collected for CBC, IL-10, and IL-17 gene expression in blood. The spleen and thymus were taken for histological and immunohistochemical studies.
Results
WBC results showed no significant difference among groups. A statistically significant higher mean IL-10 was observed among the low dose with probiotic (group 4) compared to other groups. There was a significantly higher mean of IL17 among low dose without probiotic (group 2). The mean level of IL-17 was high among group 4. Sections from thymus and spleen of MSG groups showed histological derangement. Immunohistochemical staining in tissues supported the observed gene expression levels in blood. Groups with higher cytokine gene expression generally showed stronger tissue staining, confirming consistency between transcription and protein levels and this strengthens interpretation of MSG-induced immune alterations.
Conclusion
High-dose MSG was associated with a decreased level of IL-10 with various degrees of tissue inflammation. Adding probiotics to low-dose MSG resulted in increased levels of IL-10 in blood. The low serum level of IL-17 in the high-dose MSG groups was associated with high degrees of inflammation with little improvement with probiotic.