Effects Of Simvastatin And Fosinopril On Myocardial Fibrosis And Expression Of TGP-β₁and CTGF In Rats With Chronic Heart Failure

Chronic Heart Failure （CHF） is the end-stage in various kinds ofcardiovascular disease. With the advent of aging society, prevalence rate ofCHF is getting higher and higher.At the same time, along with thepathogenesis of CHF studies deeply,the new treatment concepts are putforward. The study found that effectively inhibit cardiac remodeling bySignal Transduction path and apoptosis of the neuroendocrine-cytokinesystem, which is important to treatment and prognosis of CHF. The relation ofthe transforming growth factor-β₁（TGF-β₁） and connective tissue growthfactor （CTGF） with myocardial fibrosis has attracted much attention in recentyears. Statins is the hydroxy-methyl-glutaryl coenzyme A（HMG-CoA）inhibitor. For the past few years, research to discover Statins cure CHF haseffect of improvement of myocardial fibrosis except for therapyhyperlipemia.It is seldom reported that if the therapeutic effect of Statins isalso effective to Angiotensin converting enzyme inhibitor which has beennamed as the foundation stone of CHF curative, and if the effect ofcombination about the two drugs is superior to monotherapy. The purpose ofthe study is to investigate the effects and the molecule mechanisms ofSimvastatin and Fosinopril alone and their combination on myocardial fibrosisin rats with chronic heart failure.Objective:The model of myocardial fibrosis in rats with chronic heart failure wasestablished by abdominal aortic constriction, and investigated the effects andthe molecule mechanisms of Simvastatin and Fosinopril alone and theircombination on myocardial fibrosis in rats with chronic heart failure byobserve the expression of TGF-β₁and CTGF in treatment groups from the cellular and molecular level by immunohistochemiscal staining,Western-blot and RT-PCR.Methods:1Randomly provide10rats from60male Wistar rats as sham-operatedgroup （sham group）, and other rats were made chronic heart failure model byabdominal aortic constriction, and the left ventricular end diastolic pressure（LVEDP≥15mmHg） was taken as standard. When the chronic heart failuremodel was successfully established, residues were randomly divided into4groups, Model group, Simvastatin group, Fosinopril group, Combinationgroup（Simvastatin＋Fosinopril）, and10rats in each group. The rats in shamgroup were operated in the same way as others except for no aorticconstriction.2The rise and fall （±dp/dtmax）of Hemodynamic parameters of LVEDPand the maximum change rate of left ventricular pressure were examined bymulti-lead electric physiological instrument at the end points of each group,and the left ventricle were taken to calculation the left ventricular mass index（LVMI）.3HE and Masson staining were used to observe histopathological changeof left ventricular myocardium, and detect the collagen volume fraction （CVF）in each group.4Transmission electron microscope was used to observe theultrastructure of left ventricular myocardium.5SP immunohistochemical staining was used to observe the expressionof TGF-β₁and CTGF in left ventricular myocardium.6Werstern-blot was used to detect the level of TGF-β₁and CTGF proteinin left ventricular myocardium.7RT-PCR was used to detect the level of TGF-β₁and CTGF mRNA inleft ventricular myocardium.Results:1Hemodynamic parameters in each group: The LVEDP and±dp/dtmaxin Sham group,Model group, Simvastatin group, Fosinopril group, Combination group were （18.66±1.54） mmHg,（2840±189.63） mmHg,（4098.78±289.77）mmHg;（11.44±1.88） mmHg,（4568.34±306.11） mmHg,（3654.55±105.45）mmHg;（10.58±1.90）mmHg,（4633.37±267.35） mmHg,（3702.94±198.86）mmHg;（7.46±1.64）mmHg,（4787.65±270.32）mmHg,（4034.54±134.74）mmHg;（4.43±1.21）mmHg,（5156.20±298.56）mmHg,（4350.34±168.76）mmHg. Compared with sham group, the LVEDP wasincreased obviously （p <0.01）, the±dp/dtmax was decreased obviously in model group（p <0.01）,Compared with model group, the LVEDP was decreased obviously （p <0.01）, the±dp/dtmax was increased obviously in simvastatin group, fosinopril group andcombination group （p <0.01）, and the combination group was the lowest（p <0.01）.2LVMI and CVF in each group: The LVMI and CVF in Sham group,Model group, Simvastatin group, Fosinopril group were （2.90±0.23）‰,（33.45±2.09）%;（2.41±0.20）‰（,17.67±1.32）%;（2.53±0.16）‰,（15.86±1.42）%;（2.05±0.22）‰,（12.05±1.3）%;（1.62±0.15）‰（,8.72±1.22）%. The indexes inmodel group was higher than that in sham group （P<0.01）, and it decreasedobviously in simvastatin group, fosinopril group and combination group （p <0.01）, andthe combination group was the lowest（p <0.01）.3Histopathological change of left ventricular myocardium in each group:HE staining: In sham group, the arrangement of myocardial fibers werecompact and orderliness, the appearance of myocardial cells were normal, andthe cytoplasm texture was clear. In model groups, the arrangement ofmyocardial fibers were rarefaction, fracture and swelling, the phlogocyte wasincreased and the myocardial cells had obviously hemorrhage and necrosis. Forsimvastatin group, fosinopril group and combination group, the damage ofmyocardial fibers were much more slighter than the Model group, and thecombination group was changed obviously. Masson staining: there was notobviously collagen deposition in sham group. For model groups, a great dealof collagen deposition was revolved around the myocardial cells and bloodvessels. In simvastatin group, fosinopril group and combination group, there were afew collagen deposition. the combination group was the least.4Ultrastructure of left ventricular myocardium observed in each group: the Sham group, the arrangement of myofibrils were orderliness, the structureof organelles were normal, There was only a little collagen deposition in themyocardial interstitial. In the model groups, the myofibrils were disarranged,the structure of sarcomere was unclear, the damage of organelles were seriousand the collagen deposition increased in myocardial interstitial. For simvastatingroup, fosinopril group and combination group, the above appearance which wereobviously improved. and the combination group was changed obviously.5TGF-β₁and CTGF expression in left ventricular myocardium of rats:the Sham group, there were little or nothing of the expression of TGF-β₁andCTGF protein to be detected. In model group, expression of TGF-β₁andCTGF protein were strongly, as a lot of buffy particle was detected. forsimvastatin group, fosinopril group and combination group, the buffy particle wasobviously reduced, and the expression of TGF-β₁and CTGF protein were thelowest in combination group.6The protein and mRNA level of TGF-β₁and CTGF in left ventricularmyocardium of rats: Compared Sham group rats, The protein and mRNAlevel of TGF-β₁and CTGF in myocardium of rats in model groups increasedobviously （P<0.01）. Compared with Molel group, the protein and mRNA levelof TGF-β₁and CTGF in Simvastatin group, Fosinopril group and Combinationgroup, the differences were significant （p <0.01）. Compared with each other inmedicines control group, Above indexes improved were no significantdifference between Simvastatin group and Fosinopril group（pï¹¥0.05）.Specially in Combination group （p <0.01）.Conclusions：1Simvastatin can ameliorate myocardial collagenic remodeling in ratswith CHF, the mechanisms of which could be associated with its effect ofdown-regulating TGF-β₁and CTGF.2Both Simvastatin and Fosinopril reverse LVMI and left ventriculardiastolic dysfunction. A combination of these two drugs is superior tomonotherapy for improvement of myocardial fibrosis.