In-Vitro effect of melatonin on HT-22 cells in neurodegenerative disease model

Melatonin, a pineal gland hormone, may have neuroprotective effects and potentially be used as a treatment for neurodegenerative disorders such as Alzheimer's and Parkinson's disease. The pathogenic circumstances of neurodegenerative disorders are usually simulated in in-vitro studies employing toxic substances such as glutamate. Glutamate is an amino acid required for protein synthesis and is the most frequent neurotransmitter in the brain. Excessive glutamate synthesis in the neural cells causes excitotoxicity, oxidative stress, and neuronal death. This study examined melatonin neuroprotective properties against glutamate-induced neurodegeneration in the HT-22 hippocampus cell line. The HT-22 hippocampus neural cells were exposed to melatonin as neuroprotective and glutamate as cytotoxic. IC50 values and cell viability using an MTT assay were used to determine the effective doses. Three replicates of HT-22 hippocampal neural cells were seeded in a 96-well plate and incubated with different concentrations of melatonin at various times (24- 48 –72 h) for optimization. In addition, the study assessed the toxicity dose of glutamate at different durations, 24, 48, and 72 hours. IC50 values were calculated for each substance. Results were analyzed using a spectrophotometer at 570 nm absorbance. It is found that glutamate significantly affects cell viability compared to the control group at 2 mM concentrations and higher; 5 mM was used to perform its toxicity effect. The glutamate IC50 is 2.465 mM during 24 hours. The melatonin IC50 was calculated at 24, 48, and 72 hours as 0.8399 mM, 0.48 mM, and 0.39 mM, respectively. The results demonstrated that melatonin might exhibit a protective effect against glutamate toxicity in HT-22 neural cells. The evidence presented in this study strongly suggests that melatonin displays a neuroprotective effect against glutamate toxicity in HT-22 cells, which impacts cell viability.