Pulsed EMF stimulation increased BDNF and activated S6 levels in the hippocampus of senescent rats

Low-frequency electromagnetic field (EMF) exposure in rat has positive effects on neuronal processes in vitro. Moreover, EMF improves learning-memory and psychomotor activity during advanced ageing, but the underlying molecular mechanisms are not known in the brain. In the present study we aimed to investigate the molecular effects of chronic EMF stimulation in the hippocampus of senescent rats in vivo.Thirty months old rats were treated for six weeks with different EMF doses of 45, 95, and 1,250 µT. After sacrifice the levels of Brain Derived Neurotrophic Factor (BDNF) and activated ribosomal protein S6 as measures for protein synthesis intensity in the hippocampus were determined by Western blot analysis.The results showed that chronic EMF exposure dose dependently increased BDNF and the amount of phosphorylated S6 protein at the highest dose. The effects on the two proteins positively correlated at individual level. The results indicate that EMF exposure may enhance neurotrophic processes indicated by increased BDNF expression in the hippocampus of senescent rats. Increased phosphorylated S6 protein suggests coupling to support molecular regulation of protein synthesis.In a broader perspective, these findings may support EMF as a beneficial alternative form of passive exercise in active, exercise-limited, aged individuals.