ObjectiveTo investigate the behavioral recovery of spinal cord injury (SCI) rats that received transplantation of NEP1-40 gene-modified neural stem cells. MethodsNeural stem cells (NSCs) were derived from the cortex tissue of rat embryo at the age of 18 days and identified by Nestin immunofluorescence. The lentiviruses were transduced to NSCs to construct NEP1-40 gene modified NSCs. Spinal cords of 30 Sprague-Dawley rats were hemisected at the nineth thoracic vertebrae level. The rats were randomly assigned to three groups. Cell culture medium, NSCs and NEP1-40 gene-modified NSCs were transplanted into the lesion site of rats of SCI group, NSCs group and NEP1-40-NSCs group respectively 7 days after injury. Additional 10 rats served as blank control group (sham group), which only received laminectomy. Following transplantation, behavior tests including Basso, Beattie, Bresnahan (BBB) Locomotor Rating Scale and grid test were utilized to evaluate spinal cord functional recovery. ResultsBehavior tests 8 weeks after cells transplantation showed that the rats in SCI group got worst results, the BBB scores improved and the grid drop times reduced significantly in NSCs transplantation group (P<0.01) and behavioral test outcomes were best in the NEP1-40 gene-modified NSCs group (P<0.01). ConclusionNEP1-40 gene modification can significantly improve the behavioral recovery of SCI rats that received transplantation of pure neural stem cells. It can provide a new idea and reliable experimental base for the study of NSCs transplantation for spinal cord injury.