Exercise enhances the effectiveness of vitamin D therapy in rats with Alzheimer's disease: emphasis on oxidative stress and inflammation.

Alzheimer's disease (AD) is characterized by gradual loss of memory and cognitive functions which can affect anyone. Authors declared that there is a link between vitamin D and brain function. It has been proven that vitamin D plays an important role in improving AD cognitive functions. Researchers have found that exercise has many beneficial effects on humans. In addition to cardioprotection, it has been demonstrated that exercise provides an effective improvement in different brain functions. So in our study, we aimed to evaluate the effect of each of vitamin D and/ or exercise on AD and if they could be used as a potential line for treating AD. This study was conducted on fifty female white albino rats divided equally into 5 groups: control group, Alzheimer group induced by Lipopolysaccharide, Alzheimer group treated with vitamin D, Alzheimer group treated with exercise and Alzheimer group treated with both vitamin D and exercise. The following parameters were assessed in rat brain tissues: acetylcholine esterase (AChE) activity, levels of amyloid β 42 and tau proteins, dopamine brain neurotransmitter, BDNF and NGF by ELISA. Serum levels of IL-6 and IL-10 were assessed by ELISA. MDA, GSH and vitamin D levels were also estimated in addition to cognitive function tests and histopathological examination of rat brain tissues. In Alzheimer group, there was a significant increase in the proinflammatory cytokine IL-6, the lipid peroxidation marker MDA, amyloid β and tau proteins levels. In addition to a significant increase in time consumed in T-maze test. Alzheimer group also showed a significant decrease in the anti-inflammatory cytokine IL-10, the anti-oxidative stress biomarker GSH, the neurotransmitters AChE and dopamine, and the growth factors BDNF and NGF as well as serum vitamin D levels. Treatment with either vitamin D or exercise significantly improved cognitive dysfunction and the histopathological picture of the brains of Alzheimer's rats with the best results in combined vitamin D and exercise treated group. The treated groups, especially combined vitamin D and exercise group, showed a significant decrease in IL-6, MDA, amyloid β and tau proteins levels, but on the other hand they showed a significant increase in IL-10, GSH, AChE, dopamine, BDNF and NGF. These data suggest that combined vitamin D and exercise could be considered as a potential and effective line for treating AD.