Effect of cilazapril and aspirin on the myocardial collagen after myocardial infarction in rats

Object:The study is to compare the effects of cilazapril alone, Aspirin alone, and combination of cilazapril and Aspirin on myocardial collagen in a model of MI of rats. Method:Myocardial infarction was induced in 56 Wistar male rats by ligation of the anterior descending coronary artery. Sham-operated rats served as controls. One day (A group) after the operation, rats were randomized into 4 groups: C group (Cilazapril ), D group (Aspirin ) , E group (Cilazapril and Aspirin ), the rats who did not receive any drug treatment were in B group. After two weeks, all the rats were sacrificed. The levels of plasma angiotension II, 6-keto-PGF1a and endothelin were measured. The myocardial collagen contents (hydroxyproline levels) including infarct area, noninfarct area of left ventricular and right ventricular were assessed. Result:The myocardial collagen contents in noninfarct area of left ventricular and right ventricular were strikingly higher in four operated groups than Sham-operated group. There was no significant difference in the content of infarct area among the four operated groups. The contents in noninfarct area of left ventricular and right ventricular were reduced in C and E group compared with B group. There was no significant difference in the myocardial collagen content between C and E group, similarly between B and D group. Compared with A group, the plasma hormones (AngⅡ, ET-1) in four experimental groups were significantly increased (P0.01), but they were reduced in C and E groups compared with A group (P0.01). Compared with A group, the plasma hormone of 6-keto-PGF1a was decreased in four experimental groups (P0.01), but it was improved in C or E group (P0.01). Conclusion:AngII and ET play important roles on the myocardial collagen of postinfarct heart. cilazapril alone can improve myocardial collagen on the noninfarct area after myocardial infarction. Aspirin alone has no effect on the myocardial collagen. Combination of Cilazapril and Aspinn, the effect on myocardial collagen is similar with cilazapril alone.