Effect Of Atorvastatin On The Expression Of Cardiac Collagen In Atherosclerotic Rabbits

Objective: To investigate the change of cardiac angiotensin II (Ang II) and cardiac collagen, to determine the levels of mRNA expression of cardiac type I,III collagen and the relative value of mRNA expression of cardiac type I collagen and cardiac type III collagen; The primary purpose of this study is to explain the change and relation of cardiac Ang II and cardiac collagen in artherosclerosis and the intervention of atorvastatin;Accordingly, we may provide the theoretical evidence for primary prevention of artherosclerosis and myocardial fibrosis in coronary arteriosclerotic heart disease.Method: Twenty-four male New Zealand white rabbits were divided into three groups randomly: control group (C group, n=8), fed with basic diet, atherosclerosis group (AS group, n=8), fed with basic diet and cholesterol (1.5g/d), atorvastatin group (ATV group, n=8), fed with basic diet and cholesterol (1.5g/d) and atorvastatin (5mg/d), after 8 weeks, The morphological change of aortae was observed by HE staining, the level of cadiac Ang II was evaluated by radioimmunoassay, cardiac collagen was determined by alkaline hydrolysis, the levels of mRNA expression of cardiac type I collagen and cardiac type III collagen were determined by RT-PCR.Result: (1) Atorvastatin could significantly decrease the level of total cholesterol(TC)and low density lipoprotein-cholesterol(LDL-c); (2) The level of Ang II in AS group was significantly higher than the C group and ATV group(P<0.01); (3) The level of cardiac collagen in AS group was significantly higher than the C group and ATV group(P<0.01); (4) The levels of mRNA expression of cardiac type I collagen in AS group was significantly higher than the C group and ATV(P<0.01); the levels of mRNA expression of cardiac type III collagen in AS group was significantly lower than the C group(P<0.05); the levels of mRNA expression of cardiac type III collagen in AS group was significantly lower than the ATV group(P<0.01); the relative value of mRNA expression of cardiac type I collagen and cardiac type III collagen in AS group was significantly higher than the C group and ATV group(P<0.01); (5)The level of cardiac Ang II was positively correlated with the content of cardiac collagen (r=0.870,P<0.01); The level of cardiac Ang II was positively correlated with the levels of mRNA expression of cardiac type I collagen(r=0.874,P<0.01); the level of cardiac Ang II was negatively correlated with the levels of mRNA expression of cardiac type III collagen (r=-0.733,P<0.01).Conclusion: (1) The level of cardiac Ang II increased significantly in AS, atorvastatin could restrain the the level of cardiac Ang II; (2) The content of cardiac collagen increased significantly in AS, the levels of mRNA expression of cardiac type I collagen increased and the levels of mRNA expression of cardiac type III collgen decreased in AS; Atorvastatin could restrain the content of cardiac collagen and the the levels of mRNA expression of cardiac type I collagen, and increase the the the levels of mRNA expression of cardiac type III collagen; Atorvastatin could regulate the relative value of mRNA expression of cardiac type I collagen and cardiac type III collagen; (3) The level of cardiac Ang II was positively correlated with the content of cardiac collagen and the levels of mRNA expression of cardiac type I collagen; Inversely, The level of cardiac Ang II was negatively correlated with the levels of mRNA expression of cardiac type III collagen; (4) Atorvastatin could restrain cardiac renin-angiotensin system, and prevent the hyperplasia of cardiac collagen and the fibrosis of cardiac extracellular matrix.