Effects of spironolactone and losartan on the early neovascularization of acute myocardial infarction

The aim of the present study was to investigate the effects of spironolactone and losartan on the early healing stage of acute myocardial infarction (AMI) in rats. An AMI rat model was established and the rats were randomly divided into four groups: AMI (n=12), AMI + spironolactone (AMI + S; n=12), AMI + losartan (AMI + L; n=12) and AMI + spironolactone combined with losartan (AMI + S + L; n=12). Sham-operated rats served as a control group (n=12). The expression levels of matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) in the non-infarcted myocardium surrounding the AMI area were determined using immunohistochemistry. In addition, the capillary density in the non-infarcted myocardium surrounding the AMI area was detected. The capillary densities around the infarcted area in the AMI and treatment groups at day 7 and 14 following AMI surgery were significantly higher compared with the sham-operated rats. Compared with the AMI group, the capillary densities around the infarcted area and the ratio of MMPs/TIMP-1 were increased in the treatment groups following AMI surgery; however, the increased ratio of MMPs/TIMP-1 was reduced at day 14 following AMI surgery. Therefore, these results indicated that spironolactone and losartan may promote the formation of collateral circulation in the non-infarcted tissue surrounding the infarcted area by regulating the production of MMPs.