CELLULAR EFFECTS OF CHRONIC LOW DOSE MONOSODIUM GLUTAMATE ON CEREBELLAR NEURONS AND GLIA CELLS IN FEMALE ADULT WISTER RATS

ABSTRACT Introduction: Monosodium glutamate (MSG), a commonly used flavor enhancer, has raised concerns due to its potential neurotoxic effects, particularly on brain regions like the cerebellum that are rich in glutamate receptors. Chronic exposure to chronic low doses of SG may induce excitotoxicity, leading to neuronal and glial cell dysfunction. Objectives: This study aimed to investigate the cellular effects of chronic low dose MSG on cerebellar neurons and glial cells in female adult Wistar rats. The specific objectives included: (1) assessing histological changes in neurons, (2) evaluating morphological alterations in glial cells, (3) quantifying neuronal degeneration and glial activation, and (4) comparing cerebellar cellular profiles between control and MSG-treated groups. Methods: Fifteen (15) adult female Wistar rats were randomly assigned to three groups: Group A (control), Group D (300mg/kg MSG), and Group E (1000mg/kg MSG). Animals were treated orally for 60 days. Cerebellar tissues were processed and stained using Hematoxylin and Eosin (H&E) and Cresyl Fast Violet (CFV). Histological evaluations were conducted alongside morphometric measurements of neuronal cell area and glial cell density. Data were analyzed using ANOVA, with significance set at p < 0.05. Results: Histological examination of the control group revealed normal cerebellar layering with intact Purkinje and granular cells. Group B showed mild neuronal degeneration, pyknosis, and reduced Nissl staining, while Group C displayed severe neuronal atrophy, cytoplasmic pallor, chromatolysis, and structural disorganization. Morphometric analysis revealed a significant reduction in mean neuronal cell area: 1.95 µm² (control), 1.60 µm² (Group B), and 1.35 µm² (Group C). Glial cell density increased progressively: ~1.0 (control), 1.5 (Group B), and 1.9 (Group C), indicating escalating reactive gliosis and neuroinflammation in response to neuronal injury. All changes were statistically significant (p < 0.05). Conclusion: MSG induces dose-dependent cerebellar neurodegeneration and glial activation, supporting its potential excitotoxicity at high concentrations. Keywords: Monosodium glutamate, Cerebellum, Neuronal atrophy, Glial cell density, Excitotoxicity, Wistar rats.