Bone marrow mesenchymal stem cell transplantation enhances angiogenesis and functional recovery after cerebral ischemia in rats

Abstract

Objective To investigate the effect of bone marrow mesenchymal stem cells(BMSCs) transplantation on angiogenesis and functional recovery after focal cerebral ischemia in rats. Methods BMSCs were isolated and cultured using the whole bone marrow adherent method, and conducted phenotypic identification using flow cytometry analysis of surface positive antigen of CD29, CD90 and the negative antigen of CD34, CD45.Rats were subjected to middle cerebral artery occlusion (MCAO) for 90 minutes, and divided into three groups randomly, the sham group, model group and BMSCs group.24 hours after cerebral ischemia, rats were injected with 1ml BMSCs solution (1×106 cells/ml) or PBS via the tail vein. The modified neurological severity score( mNSS ) test, the corner test and the adhesive tape test were used to evaluate sensorimotor function on the 1, 7, 14 and 28 days after ischemia. Infarcted volume was detected by toluidine blue staining, and the numbers of vWF positive microvessels and vascular endothelial growth factor (VEGF) positive cells in the ischemic boundary were determined by immunofluorescence. Results By flow cytometric analysis, the cell phenotype of passage 3 BMSCs showed that CD29, CD90, CD34 and CD45 were 98.3%, 97.4%, 0.2% and 4.8%, respectively . Compared with the model group, BMSCs significantly reduced the score of mNSS(P<0.01), the number of right turn of corner test(P<0.05), latency of removal adhesive tape(P<0.05) and the infarcted volume (P<0.01). The numbers of vWF positive vessels and the VEGF positive cells were (42.97±8.64)/mm2 and (54.83±10.66)/mm2 at the boundary zone in model group 14 days after ischemia, respectively. BMSCs significantly increased the numbers of vWF positive vessels ((69.43±7.29)/mm2) and VEGF positive cells ((78.70±6.16)/mm2 , P<0.01). Conclusion BMSCs can improve the functions of cerebral lesions after cerebral ischemia, which may be associated with the enhanced angiogenesis and VEGF expression in the ischemic boundary. Key words: Bone marrow mesenchymal stem cells; Cerebral ischemia; Angiogenesis; Vascular endothelial growth factor