Neuroprotective effect of repetitive magnetic stimulation on primarily cultured hippocampus neurons in rats

Li WEI; Hong LIN; Zhuyi LI; Yu LIU

ABSTRACT

BACKGROUND:

Much has been studied on the neuroprotective effect of repetitive transcranial magnetic stimulation.

OBJECTIVE:

To observe the effects of repetitive transcranial magnetic stimulation on the morphology and vitality of rat hippocampus neurons in vitro in order to verify its protective effect on neurons.

DESIGN:

A completely randomized controlled experiment with animals as subjects.

SETTING:

Institute of neuroscience of a military medical university of Chinese PLA.MATERIALS The experiment was conducted at the Institute of Neuroscience, Fourth Military Medical University of Chinese PLA, from April to June 2004. Primary cultured hippocampus neurons of neonatal SD rats were used in the experiment. The cells were randomly assigned to control group,repetitive transcranial magnetic stimulation group, H2O2 group and repetitive transcranial magnetic stimulation-H2O2 group, each group having 10 wells.

METHODS:

Hippocampus neurons of the rats were cultured by common culture method. Repetitive transcranial magnetic stimulation group and repetitive transcranial magnetic stimulation-H2O2 group were treated with 1 Hz 100 mT repetitive magnetic stimulation for 1 000 times 48 hours after being seeded, whereas the control group and H2O2 group were left untreated. H2O2group and repetitive transcranial magnetic stimulation-H2O2 group were incubated with 100 μmol/L H2O2 56 hours after being seeded. Seventy-two hours after being seeded, the cellular morphology of repetitive transcranial magnetic stimulation group and control group was observed under an inverted phase contrast microscope. Cell vitality was assayed with 3-(4, 5)-dimethythioazol-2-yl-2, 5-diphenyl-tetrazoliumbromide method (MTT).MAIN OUTCOME

MEASURES:

The morphology and viability of the neurons in repetitive transcranial magnetic stimulation group and control group.

RESULTS:

Seventy-two hours after being seeded, the cellular morphology of repetitive transcranial magnetic stimulation group and control group was observed under an inverted phase contrast microscope. Cells clustered and had good refractive power. The cell body was satiated and took round, fusiform or conical shape. Processes were obvious(mostly 20-30 μm) and formed intensive neural network. The two groups did not differ significantly in morphological alteration. MTT metabolic rate It was higher in repetitive transcranial magnetic stimulation group[ ( 104.43 ± 2.76) % ] than in control group[ (100. 00 ± 3.20) % ] ( F = 1. 344, P ＜ 0.05); it was higher in repetitive transcranial magnetic stimulation-H2O2 group[ (52.61 ± 2.64) % ] than in H2O2 group[ (46. 28 ± 2.04) % ] ( F = 1. 675, P ＜ 0.05).

CONCLUSION:

After repetitive transcranial magnetic stimulation, the morphology of hippocampus neurons cultured in vitro does not change obviously, but cell vitality and ability of anti-oxidation are increased remarkably, which does not cause obvious harm to the cultured cells and may have some neuroprotective effects.