[Ultrastructural changes of rat ischemic myocardium after bone marrow mesenchymal stem cell transplantation].

OBJECTIVE

To observe the ultrastructural changes of ischemic myocardium of rats after bone marrow mesenchymal stem cells (MSCs) transplantation.

METHODS

Rat models of myocardial ischemia were established by ligating the descending anterior branch of the left coronary artery. The isolated and in vitro cultured MSCs labeled with 4' 6-diamidine-2-phenylindole (DAPI) were injected into the rats via the tail vein and the hearts of the rats were taken 1 week and 8 weeks after transplantation, respectively, for observation under fluorescence microscopy. The ultrastructural changes of the ischemic myocardium of the recipient rats were observed by transmission electron microscope.

RESULTS

The third passage of cultured MSCs growing in colonies possessed good homogeneity. One week and 8 weeks after transplantation, DAPI-labeled cells were observed in the heart of the recipient rats, but not in the hearts of control rats. One week after transplantation, ultrastructural observation identified a small number of cells in the peripherals of the infarct area of the recipient rats with similar morphology to that of MSCs cultured in vitro. At 8 weeks,a large number of capillaries were seen in the ischemic myocardium on the peripheral of the infarct area. Ultrastructural observation also revealed some immature myocytes surviving in the ischemic region.

CONCLUSION

MSCs is capable in vivo of homing to the ischemic myocardium via the blood circulation, and promote regeneration of the myocardium and blood vessels.