Objective: To investigate the possibility of homing,survival, migration and differentiation of rat mesenchymal stem cells (rMSCs) in host myocardium and the effects of rMSCs transplantation on the function of heart with myocardial infarction; To observe the feasibility of using exogenous adult stem cells for cell therapy.
Methods: 35 female rats were separated randomly into three groups: normal control group (control, n = 10), acute myocardial infarction control group (AMI, n = 10) and myocardial infarction plus cell transplantation group (AMI + Cell, n = 15). The infarcted hearts were made by occlusion of left coronary artery. Male Wistar rats MSCs were isolated and purified. Then the cells were implanted into the infarcted hearts of female Wistar rats. Heart functions were measured 10 weeks after implantation. The hearts were harvested 10 weeks after implantation for immunohischemistry.
Results: (1) Purified rMSCs survived and homed in exogenous host hearts; (2) DAPI-labelled rMSCs with oval nucleus were widely distributed and stained positively of cardiac specific proteins. The arrangements of the donated cells paralleled with host myocardium fibers in infarcted host hearts. Transplantation of rMSCs was associated with a significant decrease of end left ventricular volumes, increase of left ventricular end-systolic pressure and increase of ratio of left ventricular pressure rise and left ventricular pressure decay (+/- dp/dt) (P < 0.05) as compared with the control hearts. The numbers of blood vessels were increased at the boundary of infarction site and the sizes of infarction were decreased significantly (P < 0.05).
Conclusions: The purified rMSCs can survive in exogenous host hearts without addition of any immunosuppressant. These exogenous cells take part in myocardium regeneration and have beneficial effects on heart function.