The effects of repetitive transcranial magnetic stimulation on the injured neurons in rats

Transcranial magnetic stimulation (TMS) is a non-invasive technique employed to stimulate the brain. Recently, it has been reported that repetitive transcranial magnetic stimulation (rTMS) potentially has therapeutic effects for neurological and psychiatric disorders, such as depression and Parkinson's disease. In this study, the behavioral recovery and the protection of neuron from injury induced by the neurotoxin 1-methyl-4-phenyl-1, 2,3,6-tetrahydropyridine (MPTP) are investigated, focusing on the activation of cholinergic neuronal system in rat hippocampus. Male Wistar rats, aged 5-6, received four MPTP or saline injections at intervals of 2 hours for one day to induce the injury of neurons in the substantia nigra. Five days after MPTP or saline injections, histological experiments were performed. For statistical analysis, Kruskal-Wallis test followed by Mann-Whitney-U test was used. Sham control rats were exposed to the same noise produced during the stimulation. Results show that the neurons in the hippocampus CA3 of the MPTP/rTMS group exhibited markedly less damage than those of the MPTP/sham group. These results clearly show that rTMS protect the neuronal degeneration of hippocampus CA3. In this study it was found that acute rTMS activates the neurotransmitter/neuromodulator systems in hippocampal network in brain injured rats. In addition, the study suggests that the possibility that acute rTMS may also be clinically applicable for protection from neuronal degeneration.