Neuroprotective effects of aqueous extract of Aloe barbadensis on the cortical cells of adult Wistar rats following monosodium glutamate-induced neurotoxicity

The study assessed the oxidative state and cellular changes of the cerebral cortex following monosodium glutamate-induced neurotoxicity in Wistar rats, with a view to evaluate the effects of varying doses of aqueous extract of Aloe barbadensis (AB) over a four-week period. Eighty Wistar rats (8  weeks old) were randomly assigned into 4 groups of 20 rats; Group 1 (Control group) received 3 mL/kg of distilled water. Groups 2, 3 and 4 received 3 g/kg/day of MSG dissolved in distilled water. In addition, Groups 3 and 4 received 100 and 200 mg/kg/day of AB extract respectively. Oral administration of the above lasted for 28 days in all groups. Five rats per group were sacrificed weekly for 4 weeks. The brain was harvested; one cerebral hemisphere was homogenised for oxidative state assessment. The other hemisphere was fixed in 10% neutral buffered formalin and stained with H&E and Cresyl violet. Data were analyzed using student t-test and p-value < 0.05 was considered significant. Malodialdehyde concentration and densities of degenerating neuron and oligodendrocyte were significantly higher in group 2 compared with group 1 over the 4-week period. No significant difference was noted between groups 1, 3 and 4 for same parameters. Nissl bodies depletion was noted in group 2 across the 4 weeks, lesser degree of depletion was noted in groups 3 and 4. This study concludes that oral administration of MSG resulted in increased lipid peroxidation and depletion of Nissl bodies resulting in degeneration of cortical cells. Aloe barbadensis at 100 mg/kg was sufficient to protect the brain.