RESUMO
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).