Abstract:

BACKGROUND: Neural stem cell transplantation alone has achieved unsatisfactory outcomes in the repair of damaged spinal cord tissues. To promote the survival, proliferation and neuronal differentiation of transplanted cells in vivo, it is necessary to further improve the micro-environment of spinal cord injury.
OBJECTIVE: To investigate the effect of neural stem cell transplantation plus electroacupuncture on the hindlimb function and electrophysiological changes of rats with spinal cord injury.
METHODS: Animal models of spinal cord injury were made in 72 Sprague-Dawley rats and randomized into four groups: control group with injection of culture medium via the tail vein; neural stem cell group with injection of neural stem cell suspension via the tail vein; electroacupuncture group given 1-week electroacupuncture at Du 
meridian and body points starting from 6 hours after modeling; combined group given injection of neural stem cell suspension via the tail vein+1-week electroacupuncture at Du meridian and body points starting from 6 hours after modeling. Motor functional recovery in rats was assessed by Basso-Beattie-Bresnahan score and inclined plane test before and at 1, 3 days and 1-4 weeks after modeling. At 4 weeks after modeling, hematoxylin-eosin staining was performed for pathological observation; fluorescence microscope was used to observe the survival and distribution of CM-Dil-labeled neural stem cells; horseradish peroxidase tracer was used to observe nerve fiber regeneration; rat neurophysiological recovery was assessed by determining motor evoked potentials and somatosensory evoked potentials.
RESULTS AND CONCLUSION: At 2-4 weeks after modeling, the hindlimb function was better in the combined group than the neural stem cell group and electroacupuncture group; while it was better in the neural stem cell group and electroacupuncture group than the control group. At 4 weeks after modeling, there were few nerve axon-like structures and small voids in the spinal cord of the neural stem cell group and electroacupuncture group; however, in the combined group, there were more nerve axon-like structures and no void in the spinal cord. At 4 weeks after modeling, the number of nerve fibers positive for CD-Dil and horseradish peroxidase was ranked as follows: combined group > neural stem cell group and electroacupuncture group > control group, and there were significant differences between groups (P < 0.05). The latencies of motor and somatosensory evoked potentials were significantly lower in the combined group than the neural stem cell group and electroaucpuncture group followed by the control group (P < 0.05), whereas the amplitudes of motor and somatosensory evoked potentials were significantly higher in the combined group than the neural stem cell group and electroacupuncture group followed by the control group (P < 0.05). In conclusion, these findings indicate that neural stem cell transplantation combined with electroacupuncture can promote synaptic regeneration and improve the motor and electrophysiological functions of rats.