Repetitive Transcranial Magnetic Stimulation In Rats: Effects On The Proliferation Of Adult Neural Stem Cells And Glia Cells In Vivo And A Neuroprotective Effect In Vitro

BACKGROUND: Repetitive transcanial magnetic stimulation which is based on the principle of electromagnetic induction was introduced to the neuroscience field in 1980s. Studies to date have proved that it can be used to treat various central nervous system disorders such as depression, Parkinson disease and seizure; however, it' s precise mechanism of action has not been clearly elucidated. The adult mammalian brain harbors neural stem cells, which mainly reside in the subventricular zone of the lateral ventricle and the subgranular zone of the hippocampal formation. They usually stay at the silent period of cell cycle, but begin to proliferate after some physiological, pathologic or environmental changes. Astrocytes and microglias which express GFAP and OX-42 sepatately, make up a substantial proportion of the CNS. One of their remarkable characteristics is the vigorous response to diverse neurologic insults. They will proliferate and make some changes in the morphology responding to traumaticinjury. Today, the progresses in rTMS and adult neural stem cells suggest that rTMS may induce adult neurogenesis. OBJECTIVE: To observe the effects of rTMS on the proliferation of adult rat neural stem cells and glial cells in vivo, and the morphology and vitality of rat hippocampus neuron in vitro.METHODS: 1, The adult SD rats were treated with 1 Hz, 100 mT once a day 10 min rTMS for 14 days, being injected intraperitoneally with the mitotic marker 5-bromo- 2' -deoxy uridine(50 mg/kg/d),and then the expression of BrdU, GFAP, OX-42 and the co-labeling of BrdU with GFAP in hippocampus and dentate gyrus was investigated by ABC technique of immunohistochemistry. 2, Hippocampus neurons of the rats were cultured by common culture method. rTMS group and rTMS-H₂O₂ group were treated with 1 Hz, 100 mT rTMS for 1000 times 48 hours after being seeded, whereas the control group and H₂O₂ group were left untreated. H₂O₂ group and rTMS —H₂O₂ group were incubated with 100 μ mol/L H₂O₂ 56 hours after being seeded. Seventy-two hours after being seeded, the morphology of rTMS group and the control group was observed. Cell vitality was assayed with MTT method. RUSULTS: 1, BrdU positive cells increased after rTMS and they didn' t co-labeled with GFAP. 2 , Compared with the control group, there was no significant difference in the expression of GFAP and OX-42 between the two groups. 3, After rTMS, the morphology of hippocampus neurons in vitro didn' t change obviously, but cell vitality and anti-oxidativity were increased remarkably.CONCLUSION: rTMS using our parameters can promote the proliferation of adult rat neuron stem cells in vivo, while...