Effects of Blockage of the Renin-Angiotensin-Aldosterone System at Different Sites on Collagen Remodeling in Myocardial Infarction Rats

Objective To investigate the effects of blockage of the Renin-Angiotensin-Aldosterone system at different sites on the after rats myocardial infarction.Methods Twenty-four hours after MI model was established by ligation of the left anterior descending coronary artery,Wistar rats were randomized devided into untreated group(MI),ACEI group ARB group and SPI treated group for 2 weeks.Sham-operated rats served as controls(SHAM).The weight of rats body and heart were measured.The level of plasma AngⅡ and aldosterone were examined by radioimmunoassay.The mRNA level of cardiac collagen typeⅠand Ⅲ were measured by reverse-transcription-polymerase chain reaction(RT-PCR).Results MI enhanced heart weight(HW),heart weight index(HWI),plasma AngⅡlevel and aldosterone,expression of the mRNA level of collagen type Ⅰand Ⅲ were increased compared with sham-operated group with a significant difference(P0.01).Treated with Cilazapril,Valsartan and Sipironolactone prevented the MI-induced rise in HW,HWI significantly(P0.01).All treatment prevented the rise of cardiac collagen gene expression significantly(P0.01),and to the normal in the noninfarct zone(P0.05),but not in the infarction zone(P0.01).Conclusion MI was associated with an increase in plasma AngⅡand aldosterone,which might be involved in post-infarcted ventricular remodeling.Treated with Cilazapril,Valsartan and Sipironolactone had additive effect in attenuating the remodeling of cardial collagen after myocardial infarction.