Hoda Khalifa Abdelhady Sayed¹, Khlood Mohammed Mehdar² , Saad Misfer Alqahtani³, Haredy Hassan Haredy⁴, Sabah Elshafie Mohammed Elshafie², Amal Mohammad Shediwah⁵

Abstract

Purpose: To investigate neurotoxic effects of monosodium glutamate (MSG) on rat cerebellar cortices and evaluate potential neuroprotective action of melatonin. Methods: Adult male albino rats (40) were randomly categorized into four groups of ten rats each comprising Group I (control), Group II (melatonin-treated, 6 mg/kg/day via intraperitoneal injection), Group III (MSG-treated, 4 mg/kg/day IP) and Group IV (co-treated with MSG and melatonin). After 14 days of injections, rats were sacrificed and blood samples were collected to determine serum glucose, total cholesterol (TC) and triglyceride (TG) levels. Cerebellar tissues were processed for histological examination, and homogenized specimens were used to estimate malondialdehyde (MDA), glutathione (GSH), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) levels. Results: Administration of MSG significantly (p < 0.05) increased serum glucose, TC, TG, MDA, TNF-α and IL-1β levels while significantly decreasing GSH level (p < 0.05). Histological analysis revealed that MSG exerted degenerative effects, including the presence of pyknotic Purkinje cells, with strong positive reactions for caspase-3 and glial fibrillary acidic protein as well as weak reactions for β-cell lymphoma-2 and synaptophysin. However, melatonin administration improved these parameters. Conclusion: Monosodium glutamate induces neuronal injury in rat cerebellar cortex, but melatonin demonstrates a protective effect against these degenerative changes. There is a need for additional studies to understand the mechanisms of MSG and melatonin effects.