Effects of magnetic stimulation on proliferation and differentiation of endogenous neural stem cells/progenitor cells after spinal cord injury in rats

Objective To investigate the effects of magnetic stimulation (MS) on the proliferation and differentiation of endogenous neural stem cells (NSCs)/progenitor cells after spinal cord injury (SCI) in rats. Methods Forty-six Wistar rats were used, of which 40 were used to make an animal model of spinal cord injury (SCI) by administering a 10 g x 12.5 cm impact at the T8 level. The other 6 served as the normal controls. The SCI model rats were evenly divided into a magnetic stimulation (MS) group ( n = 20) and a control group ( n = 20). The rats in the MS group received 0.5 Hz and 1.44 T magnetic stimulation 24 h post injury, then 30 pulses per day for 7 days. The rats in the other groups were not exposed to MS. The scale of Basso, Beatti and Bresnahan (BBB) was used to assess hindlimb neurological function. Rats were sacrificed at the 24th hour, and at the 1st, 4th and 8th weeks after SCI. The ratio of nestin to microtubule associated protein 2 (MAP2)/nestin in the cells of the spinal cord was determined by immunofluorescence. Results The BBB scores in the MS group were signifi-cantly higher than those of the control group at 1, 4 and 8 weeks post SCI. Nestin and the MAP2/nestin ratios were mild in the normal spinal cords, but increased after SCI. They were higher in the MS group than that in the control groups at all time points. Conclusions MS can promote nestin expression in the spinal cord after SCI and facili-tate neural differentiation. Key words: Magnetic stimulation;  Spinal cord injury;  Neural stem cells;  Microtubule associated pro-tein 2;  Nestin