Objective: To observe the survival and differentiation of bone mesenchymal stem cells(BMSCs) into vascular endothelial cells in brain of cerebral ischemic rats after transplantation and the effect of Naomaitong(NMT) on the survival and differentiation of BMSCs. Method: Rats whole bone marrow were cultivated and BMSCs were purified and increased by methods of adherence and selection in vitro. Rats were randomly divided into different groups. Middle cerebral artery occlusion (MCAO) model was duplicated with nylon thread. Rats of transplantation and combination groups were transplanted with BMSCs via carotid artery at 24 h after operation. Electron microscopic was used to observe the microvascular endothelial cell ultrastructure of brain tissue after BMSCs transplantation. CD31+ expression in brain tissue was detected in this expertment

and the changes of Brdu/FⅧdouble labeled cells were observed by using the method of immunohistochemistry double labeling. Result: CD31+ expression was significant in brain of sham operation group

while the expression of CD31+ was significantly decreased in rats of each model group(P<0.01). In brain of 14

28 d transplantion groups

the expression of CD31+ increased obviously (P<0.01). In comparison with that of transplantation group

CD31+ expression in brain of each combination groups enhanced significantly

especially in 28 d group(P<0.01).In brain of transplantation and combination groups

survival of Brdu mark cells could be detected

and the cells increased obviously in brain of 14

28 d combination groups compared with that of transplantation group. Survival of the transplanted cells being labeled doulely by Brdu (Brdu/FⅧ) was observed in transplantation and combination groups

and the cells increased obviously in brain of each combination group than that of transplantation group. Conclusion: It is showed the tendency that the survival of BMSCs in brain tissue increase following the extension of time after transplantation

and NMT could make more BMSCs survive. The ratio of BMSCs differentiating into vascular endothelial cells enhance firstly and then weaken with the trend of the time in rats' brain after transplantation. NMT could make the servival of BMSCs enhanced after transplantation and make the differentiation into vascular endothelial cells angiogenic effect increase.