Chronic Melatonin Treatment Prevents Memory Impairment Induced by Chronic Sleep Deprivation

Abstract

Sleep deprivation (SD) has been associated with memory impairment through induction of oxidative stress. Melatonin, which promotes the metabolism of many reactive oxygen species (ROS), has antioxidant and neuroprotective properties. In this study, the effect of melatonin on memory impairment induced by 4 weeks of SD was investigated using rat animal model. Animals were sleep deprived using modified multiple platform model. Melatonin was administered via oral gavage (100 mg/kg/day). Spatial learning and memory were assessed using the radial arm water maze (RAWM). Changes in oxidative stress biomarkers in the hippocampus following treatments were measured using ELISA procedure. The result revealed that SD impaired both short- and long-term memory (P < 0.05). Use of melatonin prevented memory impairment induced by SD. Furthermore, melatonin normalized SD-induced reduction in the hippocampus activity of catalase, glutathione peroxidase (GPx), and superoxide dismutase (SOD). In addition, melatonin enhanced the ratio of reduced to oxidized glutathione GSH/GSSG in sleep-deprived rats (P < 0.05) without affecting thiobarbituric acid reactive substance (TBARS) levels (P > 0.05). In conclusion, SD induced memory impairment, which was prevented by melatonin. This was correlated with normalizing hippocampus antioxidant mechanisms during chronic SD.

Keywords: Hippocampus; Maze; Melatonin; Memory; Sleep deprivation.