Objective: Although earlier studies have shown that the transplantation of mesenchymal stem cells (MSCs) might improve cardiac functions after myocardial infraction, its role on vascular restenosis after percutaneous coronary intervention (PCI) remains controversial. The aim of this study was to investigate the effects of MSCs on the restenosis of injured artery following balloon angioplasty in a rabbit model with both myocardial infarction reperfusion and atherosclerotic stenosis carotid artery by balloon injury.
Methods: After the animal model was established for myocardial infraction reperfusion and atherosclerotic stenosis carotid artery by balloon injury, the rabbits received an intravenous transplantation of MSCs. And an equal volume of phosphate buffered solution was administered for the control group. The animal vascular tissue and myocardium tissue were excised at different time points post-transplantation and used to detect the homing of MSCs and the expressions of platelet-endothelial cell adhesion molecule-1 (CD31) and proliferating cell nuclear antigen (PCNA) by immunohistochemical staining. Four weeks later, vascular restenosis was analyzed by angiography of bilateral carotid arteries and the vascular tissues were used for histological studies.
Results: At one week post-transplantation, the 4',6-diamidino-2-phenylindole (DAPI)-labeled MSCs could be detected in myocardial infarction and injured intima. And the intimal expression of CD31 was observed at 2 weeks in the MSCs transplantation group. Yet the expression of PCNA was significantly lower in the MSCs transplantation group than that in the control group (50.5% ± 3.6% vs 23.4% ± 2.8%, P < 0.05). At 4 week post-transplantation, the neointimal area of injured vessels and the vascular restenosis were significantly lower in the MSCs transplantation group than those in the control group (0.092 ± 0.009 vs 0.189 ± 0.007, P < 0.05; 41.7 ± 3.7 vs 61.3 ± 1.6, P < 0.05). Furthermore the MSCs transplantation group demonstrated improved cardiac functions, reduced myocardial infarct size (21.7% ± 2.2% vs 34.3% ± 1.8%, P < 0.05) and significantly increased capillary density around infarction foci (33.6% ± 2.1% vs 20.8% ± 2.6%, P < 0.05) versus the control group.
Conclusion: The transplantation of MSCs plays significant roles in cardiac repairing in terms of improved cardiac functions, accelerated repair of injured vessels, suppression of neointimal hyperplasia and reduced restenosis of injured vessels.