Abstract

Alzheimer's disease (AD) is a neurodegenerative disorder associated with amyloid-beta (Ab) plaque formation and oxidative stress in the brain. Ghrelin has been proven to exert antioxidant activity and neuroprotection in different neurological diseases. This study is going on to examine the effect of ghrelin on antioxidant status in the rat's model of AD induced by Ab. Cognitive impairment was induced by intra-hippocampal administration of Ab (10 mg) in Wistar rats and ghrelin (80 mg/kg) was administrated intraperitoneal for ten consecutive days. Behavior was assessed with Morris water maze and passive avoidance tests. Malondialdehyde (MDA) level as a marker of lipid peroxidation was assessed using the thiobarbituric acid. Catalase activity was assayed by the decomposition of H2O2. Antioxidant capacity was determined using the FRAP method. Treatment with ghrelin decreased the hippocampus and serum MDA levels in wild-type rodents and prevented an increase in hippocampal and serum MDA levels in animals receiving Ab. There was no significant change in the serum catalase activity between the studied groups. Hippocampus catalase activity was reduced in the Ab group and treatment with ghrelin increased it. The antioxidant capacity of the hippocampus and serum increased in the ghrelin-receiving control group. The hippocampus antioxidant capacity level decreased in the Ab group, and treatment with ghrelin increased it, but there were no significant changes in the serum antioxidant capacity of animals receiving Ab. These results provide evidence that the administration of ghrelin has antioxidant properties and protects against hippocampal lipid peroxidation in a rat model of AD.