Objective To observe the effects of mesenchymal stem cells (MSCS) transplantation on the brain-derived neurotrophic factors (BDNF) after the spinal cord injury (SCI) of rats, and investigate the mechanism of repairing the SCI by MSCS transplantation.Methods Mesenchymal stem cells were cultured from the thighbone of adult SD rats and identified by immunoctochemistry.Seven days after the operation of spinal cord injury, the mesenchymal stem cells were transplanted into the injured spinal cord site.Sixty adult SD rats were random divided into three groups: Spinal cord injury cured with transplants of mesenchymal stem cells to the injured spinal cord site ( group A), spinal cord injury received PBS solution( group B) and control group ( group C).The expression of brain - derived neurotrophic factors of the lesion and neighbor areas were examined by immunohistochemistry, The mechanism of repairing the lesion and neighbor areas were examined by immunohistochemistry, and the mechanisms of repairing the spinal cord injury after mesenchymal stem cells transplantation were investigated.Results Mesenchymal stem cells began to grow after 24 hours of inoculation and proliferate 72 hours later.The proliferate the proliferous cyclewas 4 ～6 days, it declined on the 10th era.Mesenchymal stem cells turned to flat, and the mesenchymal stem cells could maintain the ability of proliferation if bFGF was added.Compared with group B, transplantation of mesenchymal stem cells enhanced more expression of brain-derived neurotrophic factors in group A ( 14 d :0.31 ± 0.03 vs 0.25 ± 0.04, P ＜ 0.01 ).Conclusion Mesenchymal stem cells in transplantation group showed a continued high level of brain-derived neurotrophic factors, which may be one of the mechanisms of repairing the spinal cord injury by mesenchymal stem cells transplantation.

BACKGROUND: Transplantation of bone marrow mesenchymal stem cells (MSCs) improves functional recovery after spinal cord injury (SCl), but the mechanisms involved remain unclear.OBJECTIVE: To observe the effects of MSCs transplantation on the expression of brain-derived neurotrophic factors (BDNF) in rats after SCl.DESIGN, TIME AND SETTING: Randomized, controlled, animal experiment. The study was performed at the Laboratory of Neuroanatomy, China Medical University from April to July 2003.MATERIALS: A total of 64 SD rats, aged 3 months, of either gender, weighing 250-300 g, were used. Of them, 4 were randomly selected to isolate and culture MSCs, and the remaining were used to establish SCl models.METHODS: The 60 rats were randomly divided into 3 groups. Seven days after SCl, MSCs group (n=24) was transplanted with 5 μL culture solution containing 1×109/L MSCs to the injury site using micro-injection; PBS group (n=24) was transplanted with 5μ L PBS, and the blank control group (n=12) with 5μ L normal saline.MAIN OUTCOME MEASURES: The rats were sacrificed at 7, 14, and 28 days post-surgery. MSCs morphology was observed and the expression of BDNF at the lesion areas was examined by immunohistochemistry,RESULTS: All 60 rats were included in the final analysis. After ten subcultures, the cell proliferative capacity was reduced, and cell body turned to flat; the MSCs protiferation and morphous could be maintained by adding basic fibroblast growth factor.Transplantation of MSCs enhanced the expression of BDNF compared with PBS and blank control groups at 7, 14, and 28 days post-surgery (P ＜ 0.05); white no significant difference was found between PBS and blank control groups (P ＞ 0.05).