Protective role of Krill oil against estrogen deficiency induced neurodegeneration in ovariectomized rats

Marine oils are rich in long-chain polyunsaturated omega-3 fatty acids and known to be associated with health promoting effects, particularly on learning memory and prevention of neurodegenerative diseases by decelerating cognitive decline. Krill oil (KO) is novel marine oil rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and the antioxidant astaxanthin (ASTA) which play central role in oxidative stress in neuronal metabolism. In the present study, the possible protective role of KO against learning and memory impairment as well as brain oxidative damage induced by ovariectomized (OVX) rats either alone or combined with γ-radiation was investigated. Our data revealed that OVX rats, alone or with γradiation, induced a significant decrease in the levels of estrogen (E), serotonin (SER), dopamine (DA), insulin growth factor-1 (IGF-1) and the gene expression of brain-derived neurotrophic factor (BDNF) mRNA, Selective AD Indicator-1 (SELADIN-1) mRNA associated with a significant elevation in malondialdehyde (MDA), amyloid precursor protein (APP) mRNA and glycogen synthase kinase-3beta (GSK-3β) mRNA, acetylcholinesterase (AChE) and norepinephrine (NE). Treatment with KO to OVX rats, alone or with γ-radiation, resulted in significant amelioration of all investigated parameters. This study has confirmed the protective effect of Krill oil against memory impairment and thereby preventing the development of Alzheimer disease.