| Purpose: Low frequency pulsed electromagnetic field(LFPEMF)has been proven to have protective and nutritional effects on the nervous system.However,there are no reports on whether LFPEMF can treat spinal cord injury(SCI)and its therapeutic mechanism.Therefore,this study was conducted to investigate whether LFPEMF can promote the recovery of neurological function after SCI in rats and its therapeutic mechanism.Methods: SD rats were randomly divided into sham operation group,spinal cord injury group and treatment group,and SCI model was constructed by NYU impactor.The Basso-Beattie-Bresnahan(BBB)score and Transcranial magnetic motor evoked potentials(tc MMEPs)were used to evaluate the recovery of neurological function after SCI in rats.Hematoxylin and eosin(HE)staining and Luxol fast blue(LFB)staining were used to assess the severity of spinal cord injury after SCI in rats.Immunofluorescence(IF)and Western Blot(WB)were used to assess the differentiation and maturation of oligodendrocytes after SCI in rats.Toluidine blue(TB)staining was used to assess remyelination after SCI in rats,including the number of myelinated fibers and myelin thickness.WB and Enzyme-linked immunosorbent assay(ELISA)were used to evaluate the expression of neurotrophic factors and inflammatory factors after SCI in rats.The random distribution of experimental subjects,the establishment of rat spinal cord injury model,data collection,data analysis and other research processes all abide by the "blind method".Results: The results of BBB scores showed that the means BBB score of the rats in the treatment group were significantly higher than those in the spinal cord injury group at 3-8 weeks after operation,and the differences were statistically significant(P<0.05).The results of tc MMEPs showed that the rats in the treatment group showed shorter latency and higher amplitude than the spinal cord injury group at 2-8 weeks after operation,and the difference was statistically significant(P<0.05).The results of HE staining showed that the severity of SCI in the treatment group was significantly lower than that in the spinal cord injury group at 14 days after operation,and the difference was statistically significant(P<0.05).The results of LFB staining showed that the severity of destruction and demyelination of spinal cord tissue in the spinal cord injury group was more severe than that in the treatment group at 14 days after operation,and the difference was statistically significant(P<0.05).The results of IF staining showed that the number of mature oligodendrocytes in the spinal cord of the treatment group was significantly higher than that in the spinal cord injury group at 4,7 and 14 days respectively after operation,and the differences were statistically significant(P<0.05).The results of WB showed that the expression of MBP(Myelin basic protein)in the spinal cord of the treatment group was significantly higher than that in the spinal cord injury group at 7 days after operation,and the difference was statistically significant(P<0.05).The results of TB staining showed that the number of myelin fibers and myelin thickness in the spinal cord of the treatment group were significantly higher than those in the spinal cord injury group at 1,2 and 3 weeks respectively after operation,and the differences were statistically significant(P<0.05);The results of WB showed that the expression of BDNF(Brain derived neurotrophic factor)and NGF(Nerve growth factor)in the spinal cord of the treatment group were significantly higher than those in the spinal cord injury group at 3 days after operation,and the differences were statistically significant(P<0.05).The results of ELISA showed that the expression of TNF-α(Tumor necrosis factor-α)and IL-6(Interleukin-6)in the spinal cord of the treatment group were significantly lower than those in the spinal cord injury group at 24 h after operation,and the differences were statistically significant(P<0.05).Conclusions: LFPEMF can promote the recovery of neurological function in rats after SCI by improving differentiation and maturation of oligodendrocytes and promoting remyelination,as well as by inhibiting inflammation and promoting neurotrophic effects. |
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