The study of the neuroprotective effects of curcumin, against homocysteine intracerebroventricular injection –induced cognition impairment and oxidative stress in the rat

Introduction: Aging is the major risk factor for neurodegenerative diseases and oxidative stress is involved in the pathophysiology of these diseases. Oxidative stress can induce neuronal damages and modulate intracellular signaling, ultimately leading to neuronal death by apoptosis or necrosis. Methods: In this study, we investigated the possible antioxidant and neuroprotective properties of the polyphenolic antioxidant compound, Curcumin against homocysteine (Hcy) neurotoxicity. Curcumin (5, 15, 45 mg/kg) was injected intraperitonealy once daily for a period of 10 days beginning 5 days prior to Hcy (0.2 μmol/μl) intracerebroventricular injection in rats. Biochemical and behavioral studies, including passive avoidance learning and locomotor activity tests were studied 24 h after the last curcumin or its vehicle injection. Also Histopathological studies and cell dencity in different regions of hippocampus was investigated. Results: Hcy could induce lipid peroxidation and increase MDA and SOA levels in rats' brain. Additionally, Hcy impaired memory retention in passive avoidance learning test. However, Curcumin treatment decreased MDA and SOA levels significantly as well as improved learning and memory in rats. Histopathological analysis also indicated that Hcy could decrease hippocampus cell count and Curcumin inhibited this toxic effect. Conclusion: These results suggest that Hcy may induce lipid peroxidation in rats' brain and decrease hippocampus cells. Also polyphenol treatment (Curcumin) has the ability to improve learning and memory deficits by protecting the nervous system against Oxidative stress. Keywords: Homocysteine, Curcumin, Lipid peroxidation, Oxidative Stress