Effects of exercise on memory of mice with dementia and possible mechanisms

Objective To investigate the effects of exercise on memory impairment in demented mice and possible molecular mechanisms. Methods Thirty Kunming nice were divided into a normal control group,a dementia group and a dementia plus exercise training group (exercise training group),10 mice/group. Dementia models were established by intraperitoneal injection of scopolamine.Exercise training was begun 30 min after the injection and lasted for a 6-week period. A water maze test was performed after the exercise training. Brain-derived neurotrophic factor (BDNF) expression and protein kinase (Akt) phosphorylation in the hippocampus were detected by Western blot analysis.Nitric oxide (NO) content and superoxide dismutase (SOD) activity in the hippocampus were also measured. Results Dementia models were successfully induced as indicated by prolonged escape latency in the water maze test.After exercise training the escape latency had shortened significantly and hippocanpal BDNF expression and Akt phosphorylation had increased.NO content increased and SOD activity decreased after the injections,but these effects were partially reversed after exercise training. Conclusions Exercise can improve spatial memory significantly after scopolanine-induced dementia in mice.The increased hippocampal BDNF expression and Akt phosphorylation,increased SOD activity and decreased NO content may partially explain the behavior improvement induced by exercise. Key words: Exercise ;  Dementia ;  Water maze test