MSCs Engraftment Regresses Myocardium Fibrosis and Improves Heart Function in Spontaneously Hy- pertensive Rat

Objective To explore the effects of mesenchymal stem cells (MSCs) on myocardial fibrosis in hypertensive rat and try to find a novel way to regress ventricular remodeling and improve the organ damage in hypertension. Methods Twelve weeks old spontaneously hypertensive rats and age-matched Wister rats were used. MSCs were prepared from healthy rats and cultured for 14 days. The cells were transplanted to SHR by direct injection to left ventricule, every rat received 1×106cells once. Four weeks later, rats were sacrificed. Left ventricular mass, end-dias-tolic volume and cross-sectional area of myocardium and collagen volume fraction(CVF) were calculated. The expression of homeoxygenase-1 were evaluated by immuneochemistry method. Results Pressure-volume curve demonstrates that LV compliance in mesenchymal stem cells transplantation was better than that in SHR control group, although it was lower compared with Wister rat (P 0.05). Pathologic examination showed obviously reduction of collagen volume fraction in study group, especially type Ⅰ collagen. MSCs increased the expression of HO-1 in myocardium (P 0. 05). However, MSCs transplantation didn't increase left ventricular mass and improve the ventricular hypertrophy. Conclusion MSCs transplantation regulate collagen content in heart by inhibiting synthesis or stimulating degradation of collagen through HO-1 way. Regression of myocardial fibrosis and ventricular remodeling, may eventually lead to function improvement.