Effect of brain-derived neurotrophic factor and green fluorescent protein gene-transfected neural stem cells transplantation on brain-derived neurotrophic factor expression in rats with spinal cord injury

Objective To study the effect of brain-derived neurotrophic factor（BDNF） and green fluorescent protein（GFP）-transfected neural stem cells（NSCs） transplantation on expression of BDNF in rats with spinal cord injury.Methods NSCs were transfected with adenovirus vector bearing BDNF and GFP.Expression of BDNF in BDNF and GFP-transfected NSCs was detected by immunohistochemistry and Western blot,respectively.Of the 40 healthy Wistar rats,8 were selected as a sham-operation group,32 served as a T9 left hemisection model.Then,the 32 rats were randomly divided into BDNF and GFP-transfected NSCs transplantation group,GFP-transfected NSCs transplantation group,single NSCs transplantation group and model groups,8 rats in each group.Gene-transfected NSCs or non gene-transfected NSCs were microinjected into each side of the transection site in the 3 NSCs transplantation groups after spinal cord injury（SCI） was induced.An equal volume of PBS was injected into the model group through the same injection sites.Expression of BDNF was detected in each group after SCI by real-time PCR.Results Immunohistochemistry showed that BDNF and GFP-transfected NSCs could express BDNF（yellow fluorescence）.Western blot demonstrated that BDNF and GFP-transfected NSCs could express immunoreactive bands with a relative molecular mass of 41kU.NSCs transplantation could significantly increase the expression level of BDNF（P＜0.01）.The expression level of BDNF was the highest in BDNF and GFP-transfected NSCs transplantation group（P＜0.01）.Conclusion BDNF and GFP-transfected NSCs can survive and highly express BDNF in hemisected spinal cord model of rats.