Abstract: Objective To investigate the effect of Shexiangbaoxin Pills(SXBXP) on the messenger RNA(mRNA) levels of α₁-adrenergic receptor(AR) and β-AR expressed in non-infarcted left ventricular tissue from rats with chronic heart failure(CHF) induced by myocardial infarction.Methods Models of CHF established by anterior descending coronary artery ligature.Fifty-four Wistar rats were randomly divided into five groups:control group(group A),sham operation group(group B),CHF model group(group C),positive medicine group(group D),low dose SXBXP group(group E) and high dose SXBXP group(group F).Heart function was determined by echocardiography,mRNA expression levels of β₁-AR,β₂-AR,β₃-AR,α_1A-AR,α_1B-AR,α_1D-AR in non-infarcted left ventricular tissue were measured by semiquantitative reverse transcription polymerase chain reaction(RT-PCR).Results ① Before therapy,there was no significant difference between groups A and B.Compared with group B,the left ventricle ejection faction(LVEF) of groups C,D,E and F were significantly decreased(P<0.01).After therapy,compared with group C,LVEF of group F was significantly improved(P<0.05).LVEF of groups D and E increased even no significant difference was detected compared with group C.② After therapy,no significant change was seen in expression of any adrenergic receptor in groups A and B(P>0.05).Compared with group B,β₁-AR and α_1B-AR expression in group C markedly decreased(P<0.01 and P<0.05),expression of α_1A-AR and β₃-AR exhibited a remarkable increase(P<0.01),while there was no significant difference in β₂-AR and α_1D-AR expression between groups B and C(P>0.05).Compared with group C,levels of β₁-AR and α_1B-AR significantly increased(P<0.05 or P<0.01),α_1A-AR markedly declined in groups D,E and F(P<0.05),β₂-AR and α_1D-AR expression remained unchanged in these groups(P>0.05).β₃-AR level significantly declined in both groups D and F(P<0.01) compared with group C.Conclusion Heart function was improved and levels of LVEF was increased when SXBXP was used to treat rats with CHF induced by myocardial infarction.The action of SXBXP in CHF may be related to better blood supply to myocardium and regulation of α₁-AR and β-AR expression towards normal,including the upregulation of β₁-AR and α_1B-AR and downregulation of α_1A-AR and β₃-AR.This observation supports the hypothesis that SXBXP may improve CHF,especially when it is applied at large dose.

Key words: heart failure, myocardial infarction, rat, adrenergic receptor