Migration of intravenously grafted mesenchymal stem cells to injured heart in rats.

The present study aimed to determine the role of tissue injury in migration of mesenchymal stem cells (MSCs) intravenously transplanted into heart and to establish experimental basis for improving stem cell therapy in its targeting and effectiveness. MSCs were isolated from bone marrow of male Sprague-Dawley rats and purified by density centrifuge and adhered to the culture plate in vitro. Female rats were divided randomly into four groups. Myocardial ischemia (MI) transplanted group received MSCs infusion through tail vein 3 h after MI and compared with sham-operated group or normal group with MSCs infusion, or control group received culture medium infusion. MI was created in female rats by ligating the left anterior descending coronary artery. The heart was harvested 1 week and 8 weeks after transplantation. The characteristics of migration of MSCs to heart were detected with expression of sry gene of Y chromosome by using fluorescence in situ hybridization (FISH). Ultrastructural changes of the ischemic myocardium of the recipient rats were observed by transmission electron microscope (TEM). One week or 8 weeks after transplantation, sry positive cells were observed in the cardiac tissue in both of MI transplanted group and sham-operated group, the number of sry positive cells being significantly higher in MI transplanted group (P<0.01). No significant difference was found in the number of sry positive cells between 1 week and 8 weeks after transplantation. No sry positive cells were observed in the hearts of control and normal group. In addition, the ultrastructure of some cells located in the peri-infarct area of MI rats with MSCs transplantation was similar to that of MSCs cultured in vitro. These results indicate that MSCs are capable of migrating towards ischemic myocardium in vivo and the fastigium of migration might appear around 1 week after MI. The tissue injury and its degree play an important role in the migration of MSCs.