Effect of melatonin on hippocampal CA3 pyramidal cells following dexamethasone treatment in mice

Prolonged exposure to dexamethasone (DEX), a synthetic glucocorticoid receptor agonist, has been shown to induce neuronal cell death in the hippocampus. Cell death is particularly pronounced in the CA3 pyramidal neurons, inducing cognitive dysfunction. The aim of this study was to investigate the effect of melatonin on hippocampal CA3 pyramidal cells in dexamethasone treated mice. The mice received a daily injection (i.p.) of dexamethasone at 60 mg/kg for 21 days. Melatonin (10 mg/kg) was injected (i.p.) before dexamethasone treatment for 30 minutes. Hippocampal CA3 damage was investigated by 0.1% cresyl violet staining. The co-treatment with melatonin 30 min prior to dexamethasone was found to significantly protect against the morphological changes and neuronal loss in the CA3 region. These results suggest that melatonin may have a protective effect against neuronal cell damage following dexamethasone treatment, and this may be helpful for improving brain cognitive function.