Neurotrophic and antioxidant effect of rTMS in Alzheimer-s Disease.

Abstract

Aims: Repetitive Transcranial Magnetic Stimulation (rTMS) is a neuromodulation tool recently suggested for as a means of intervention in neurodegenerative diseases. Many studies have revealed via neuropsychological testing that rTMS promotes cognitive and behavioral improvements. However, the neurotrophic and antioxidative efficacy of rTMS has not been well investigated in neurodegenerative diseases. The brain-derived neurotrophic factor (BDNF) modulates neurotransmitters and plays an important role in the survival of neurons, growth of synapses and differentiation of new neurons arising from projector cells. Oxidative stress is one of the main factors that threaten neuronal survival. The purpose of this study was to investigate the effects of rTMS on neurotrophic and antioxidative factors in Alzheimer-s Disease (AD).Methods: 20 Hz rTMS was applied to the left lateral parietal cortex of 18 patients with AD (CDR≥1 age AVG and SD: 70.05±7.86) for ten days. Blood samples were collected before and 2 weeks after the rTMS sessions. BDNF levels were measured to detect neurotrophic changes in the stored samples. Oxidative stress index (OSI), total thiol, native thiol, and disulfide metabolite levels were measured to detect antioxidative changes.Results: BDNF (p<0.05), total thiol (p<0.002), and native thiol (p<0.0001) levels were increased, while OSI (p<0.001) and disulfide (p<0.001) levels decreased after rTMS. Additionally, there was a correlation between BDNF and total thiol (p<0.05)/native thiol levels (p<0.02).Conclusions: In metabolic reactions, thiol levels decrease in the oxidation process, while disulfide bonds increase. In conclusion, rTMS both increased neurotrophic activity and reduced oxidative stress.