Protein Expression of Matrix Metalloproteinase-2 in Heart of Hypertensive Rats and Its Changes After Blockage of RAS

[Objective] To observe matrix metalloproteinase-2 (MMP-2) protein expression in the left ventricular myocardium of stroke-prone spontaneously hypertensive rats (SHRSP) , and to evaluate the effects of combination of ACEI and ATI-ant as wall as the effects of either agent alone on MMP-2 protein expression. [Methods] 40 male SHRSP, eight-week-old, were randomly separated into 5 groups ( n = 8), including:①SHRSP control group,②) placebo treated group, ③valsartan treated group, ④ benazepril treated group, ⑤ combination treated group with valsartan and benazepril. In addition, 8 male Wistar-Kyoto rats (WKY), aged 8 wkkes, were used as control. MMP-2 protein expression in left ventricular myocardium of rats was detected by immunohistochemical staining. [Results] Systolic blood pressure (SBP), Left ventricular mass index (LVMI), CVF (collagen volume fraction) , PVCA (perivascular collagen area), and MMP-2 protein expression increased significantly in SHRSP compared with WKY, and decreased significantly after drug therapy. There were no differences in SBP, LVMI, CVF, PVCA, and MMP-2 protein expression between valsartan and benazepril group, but these indexes deceased more remarkably in the combination group than in the valsartan or benazepril group. [Conclusion] There is an increase in MMP-2 protein expression in the left ventricu- lar myocardium of SHRSP. After blockage of RAS, MMP-2 protein expression decreases remarkably in left ventricular myocardium of SHRSP. These effects may be in part responsible for the effect of be-nazepril or valsartan on reversing left ventricular remodeling. Benazepril/valsartan combination offers a better therapeutic effect on lowering SBP, and reversing ventricular remodeling in SHRSP than the treatment with either agent alone.