Effects of Atorvastatin on myocardial fibrosis and cardiac TNF-α after myocardial Infarction in rats

【Objectives】To investigate the effect of Atorvastatin on myocardial fibrosis and cardiac TNF-α after myocardial infarction in rats.【Methods】The rat model of MI was established by ligating the left coronary artery in female Wistar rats.Three hours after the ligation,25 survived rats were randomly divided into Atorvastatin group,MI group and sham operation group.The rats were lavaged with 10 mg/(kg.d)Atorvastatin in Atorvastatin group.And tap water in MI and sham operation groups for 4 weeks.The left ventricular transverse diameter(LVTD),which indicates the changes of left ventricular struture,was detected.The collagen volume factor(CVF)in non-infarcted and in-farcted myocardium was detected with VG staining and the content of angiotensin Ⅱ in non-infarcted myocardium was determined with radioimmunoassay.TNF-α was examined with immunohistochemical method.【Results】There were no significant difference in MI size and infarcted zone CVF between the MI and Atorvastatin groups.Compared with the sham operation group,LVTD,CVF and the content of angiotensin Ⅱand TNF-α in non-infarcted my-ocardium were all significantly increased in MI group.The location of TNF-α was mainly cardiac interstitium.The expression of this cytokine was not confined to the infarct but also could be detected in cardiac myocytes within the noninfarcted myocardium.LVTD,CVF and the content of angiotensin Ⅱand TNF-α in Atorvastatin group were all significantly lower than those in MI group.【Conclusion】Atorvastatin may improve the myocardial fibrosis after MI without affecting infarct healing by inhibiting the overexpression of angiotensin Ⅱand TNF-α.