Paracrine of bone marrow mesenchymal stem cells promotes angiogenesis in rats with spinal cord injury

Abstract

Objective To explore the effects of paracrine of the transplanted bone marrow mesenchymal stem cells (BMSCs) on angiogenesis in rats with spinal cord injury (SCI). Methods BMSCs were isolated, purified and cultured in vitro by Percoll density gradient centrifugation combined with adherent method. The specific cellular surface marker CD34, CD45, CD29 and CD90 of BMSCs were analyzed with a flow cytometer. The rat SGI model was prepared according to the Allen method. 54 healthy adult Sprague-dawely (SD) male rats were randomly divided into sham-operation group, control group and experimental group. BMSCs were injected 3 days after injury in sham-operation and experimental groups via the caudal vein, and PBS was injected in control group. Expression of VEGF and bFGF in transplanted BMSCs labeled with CFSE was observed at 1, 7 and 14 days after transplantation by immunofluorescence staining under laser confocal scanning microscopy. Influence of transplanted BMSCs on expression of factor Ⅷ related antigen in injured spinal cord was detected by immunohistochemical method. Influence of transplanted BMSCs on expression of VEGF and bFGF mRNA in injured spinal cord was detected by RT-PCR method. Results Under laser confocal scanning microscopy, the transplanted BMSCs could gather together and live in injured spinal cord and express VEGF and bFGF. Compared with control rats, the gray value of factor Ⅷ related antigen in the injured spinal cord of experimental rats was significantly higher, the micro-vessel density was significantly greater, and the expression of VEGF and bFGF mRNA was significantly higher ( P < 0. 05). The micro-vessel density and the expression of VEGF and bFGF mRNA on day 14 after transplantation in the experimental group were significantly higher than on day 1 and day 7 (P < 0. 05). Conclusion The transplanted BMSCs may promote structural and functional recovery of the injured spinal cord by paracrining VEGF and bFGF and increasing micro-vessel density in the injured spinal cord after SCI in rats. Key words: Bone marrow; Mesenchymal stem cells; Spinal cord injury; Basic fibroblast growth factor; Vascular endothelial growth factor