Objective： To explore a new method to treat brachial plexus root avulsion experimentally by reimplantation combined with transplantation of neural stem cells （NSCs） modified by neurotrophin-3 gene （NT-3）. Methods： The total RNA was extracted from neonatal rat striatum and the NT-3 cDNA was obtained by reverse transcription and amplified by polymerase chain reaction. The NT-3 gene was transferred into NSCs via the pLEGFP-C 1, an expression plasmid vectors. The untransfected NSCs, the pLEGFP-C 1 treated NSCs, and the pLEGFP-C 1-NT-3 treated NSCs were transplanted into corresponding spinal cord segment with brachial plexus root avulsion. The survival, differentiation, and migration of the transplanted cells were determined under confocal laser scanning microscope or by immunohistochemistry method. The nerve regeneration was evaluated by gross observation, electrophysiological examination and reverse horseradish peroxidase tracing. Results： The NT-3 gene was successfully amplified and transferred into neural stem cells via the plasmid vectors. The transplanted cells survived, differentiated, and migrated and NT-3 was expressed within the spinal cord. The animals regained some muscle strength which was less than 3-degree muscular strength according to the British Medical Research Council （BMRC） evaluating system. The resuits of electrophysiological examination and reverse horseradish peroxidase tracing were superior in the pLEGFP-C 1- NT-3 group to the NSCs untransfected group or the pLEGFP- C1 group. Conclusion： Transplantation of NSCs modified by NT-3 gene combined with reimplantation is a relatively effective way to treat brachial plexus root avulsion experimentally. It still need further study to improve the results.
