The role of MAPK signaling pathway in selenium amelioration of high fat/high cholesterol diet-induced tauopathy in rats

MAP kinases, CREB, and Tau are signaling molecules among downstream synaptic targets involved in synaptic function, memory formation and cognition. Here we investigate the neuro-protective effect of selenium in HFHCD induced tauopathy and cognitive impairment in rats. The study was focused on the effects on synaptic plasticity related molecules in hippocampus, which in turn may be the mechanism responsible for underlying behavior alterations. Rats were divided into 2 main groups: one fed with normal rat chow diet and the other with HFHCD for 6 weeks. Every group was subdivided into three subgroups, non-treated, low dose Se (200 μg/kg) and high dose Se (400 μg/kg). The cognitive behaviors of the rats were tested using the Morris Water Maze test, hole board and conditioned avoidance tests. Daily administration of Se decreased the observed memory impairment induced by HFHCD as measured by behavioral tests. It significantly alleviated oxidative stress and restored protein expression of cyclic AMP response element protein (CREB) and brain derived neurotrophic factor (BDNF) and reduced p-Tau in the hippocampus. Se reversed HFHCD-induced cognitive impairments via decrease expression of p38 MAPK that phosphorylate and aggregate Tau protein. Addition, It restored neuronal plasticity through increasing the expression of BDNF, and CREB in the hippocampus; thus, it can be considered as a possible beneficial therapeutic approach for prevention and treatment of HFHCD induced tauopathy and cognitive impairment, further studies are warranted in this field.