Effect Of Simvastatin On Smads Protein Expression In The Infarcted Rat Heart

Objective To investigate Smad3 and Smad7 proteins expression in different regions of cardiac tissue after myocardial infarction,and the effect of Simvastatin on their expression.Methods The rat models with myocardialinfarction were established by coronary artery 1igation andrandomized into following groups:M I group( n=12),Simvastatin group ( n=12),and Sham -operation group( n=12).The animals were sacrificed at the fourth weekend.We examined heart weight/body weight ratio(HW/BW),cardiomyocyte cross-sectional area (CSA),were examined.Smad3 and Smad7 mRNA was measured by reverse transcription polymerase. Smad3 and Smad7 Prorein was measured by Western blotting.Results1. Compared with sham—operated rats ,the left ventricular weight index,Cardiomyocyte cross-sectional area,CollagenVolume Fraction increased in MI group and SIM group(P <0.05),the expression of Smad3mRNA(0.89755±0.0450→0.65273±0.0222,P <0.05),the protein production of Smad3 ( 0.51671±0.0302→1.39201±0.0554 , P <0.05 ) significantly increased in MI group。Smad7mRNA(0.98251±0.0271→0.53975±0.0325,P <0.05) , protein production of Smad7 ( 0.94597±0.0216→0.58459±0.0616 , P <0.05 ) significantly decreased in MI group。Compared with sham—operated rats , the expression of Smad3mRNA(0.31825±0.0352→0.89755±0.0450,P <0.05)the protein production of Smad3(0.51671±0.0302→0.65273±0.0222,P <0.05)increased in SIM group。Smad7mRNA(0.98251±0.0271→0.66312±0.0344,P <0.05)and protein production of Smad7 ( 0.94597±0.0216→0.68857±0.0325 , P <0.05 ) significantly decreased in SIM group。2. Compared with MI group, LVWI(2.40±0.18→1.89±0.05 mg/g,P <0.05),CSA(2427802±214256→1465827±124190 um2,P <0.05),CARP ( 5.48±0.32 %→4.27±0.22 %, P <0.05 ),the expression of Smad3mRNA(0.89755±0.0450→0.65273±0.0222,P <0.05),the protein production of Smad3(1.39201±0.0554→1.21937±0.0228,P <0.05)decreased in SIM group。Smad mRNA(0.53975±0.0325→0.66312±0.0344,P <0.05)and protein production of Smad7 ( 0.58459±0.0616→0.68857±0.0325 , P <0.05 ) significantly increased in SIM group Conclusions1 Smad3 are upregulated and Smad7 are downregulated in rats with MI.2 Simvastatin could alleviate myocardial fibrosis after MI, and the effect is partly via down-regulation of Smad3 and up-regulation of Smad7.