Protective effect of melatonin on brain injury of cerebral ischemia/reperfusion and its mechanism

Abstract

Objective To investigate the protective effect of melatonin on brain injury in rats with cerebral ischemia/reperfusion and its mechanism. Methods Ninety rats were divided into control group, model group and melatonin group accorded to random number method, thirty rats in each group. The cerebral infarction volume and neurobehavioral score of rats were determined. The C/EBP homologous protein (CHOP), phosphorylated pancreatic endoplasmic reticulase (p-PERK), glucose-regulated protein 78 (GRP78) and cleaved caspase-3 protein levels were determined by Western blotting analysis. The levels of CHOP, PERK and GRP78 mRNA in rat brain tissue were determined by reverse transcription-polymerase chain reaction (RT-PCR). Used t test and analysis of variance. Results The cerebral infarction volume [(17.83±1.46)%] and neurological deficit scores [(1.34±0.22) scores] of the melatonin group were lower than those of the model group [(44.25±2.92)%, (3.12±0.46) scores](t=30.280, 18.472, P<0.05). Compared with the control group, the levels of CHOP, p-PERK, GRP78 and cleaved caspase-3 protein in the brain tissue of the model group and the melatonin group were increased (F=22.879, 47.469, 25.788, P<0.05). Compared with the model group, the levels of CHOP, p-PERK, GRP78 and cleaved caspase-3 protein in the brain tissue of the melatonin group were decreased (t=5.134, 6.274, 5.618、4.382, P<0.05). Compared with the control group, the levels of CHOP, PERK and GRP78 mRNA in the brain tissue of the model group and melatonin group were increased (F=65.940, 23.848, 16.277, P<0.05). Compared with the model group, the levels of CHOP, PERK and GRP78 mRNA in the brain tissue of melatonin group were decreased (t=7.463, 5.164, 4.026, P<0.05). Conclusion Melatonin has a protective effect on brain tissue of rats with cerebral ischemia/reperfusion, and its mechanism may be that melatonin exerts brain protection by inhibiting endoplasmic reticulum stress in brain tissue. Key words: Melatonin; Brain; Ischemia/reperfusion; Rat; C/EBP homologous protein; Phosphorylated pancreatic endoplasmic reticulum kinase; Glucose regulatory protein 78