Objective To explore the possible mechanism of Qishen Granule（芪参颗粒） in the treatment of myocardial fibrosis in rats with heart failure after myocardial infarction.Methods A total of 50 SD rats were randomly divided into a sham operation group with 15 rats

a model group with 12 rats

a Qishen Granule group with 12 rats and a fenofibrate group with 11 rats.Except for the sham operation group

the rats in the other groups performed left heart coronary artery ligation to induce heart failure model after myocardial infarction.The Qishen Granule group was given18.66 g/（kg·d） Qishen Granule by gavage.The fenofibrate group was given fenofibrate 10 mg/（kg·d） by gavage.The sham operation group and the model group were given the same volume of normal saline.The rats were administered for 28 days.The cardiac function and the pathological changes of myocardial tissue in each group were observed.The expression of transforming growth factor β（TGF-β）

Smad3

Wnt1 a

β-catenin

Wnt1 induced secreted protein 1（WISP-1）

and Wnt5 a protein content in rat myocardium were detected by Western blot.Results Compared with the sham operation group

the left ventricular ejection fraction（EF） and fraction shortening（FS） of the model group were significantly decreased

and the left ventricular internal diameter at end-diastole（LVIDd） and the left ventricular internal diameter at end-systolic（LVIDs） were significantly increased（P<0.01）;Compared with the model group

the EF and FS of the Qishen Granule group were significantly increased

and the LVIDd and LVIDs were significantly decreased.The EF and FS of the fenofibrate group were significantly increased

and the LVIDs were significantly decreased（P<0.05 or P<0.01）.HE staining showed that the myocardial cells in the model group were disordered

and a large number of inflammatory cells infiltrated in the myocardial interstitial

excessive collagen deposition

significant fibrosis and loss of normal structure.The cells of the Qishen Granule group and the sham operation group were arranged neatly

and the cell morphology basically showed no change.Only a small amount of collagen deposition

and myocardial fibrosis was improved.Compared with the sham operation group

the expression of TGF-β

Smad3

Wnt1 a

β-catenin

WISP-1 and Wnt5 a protein was increased in the model group（P<0.05 or P<0.01）.Compared with the model group

the Qishen Granule group and the fenofibrate group The protein levels of TGF-β

Smad3

Wnt1 a

β-catenin

WISP-1 and Wnt5 a in the fenofibrate group were decreased（P<0.05 or P<0.01）.There was no statistically significant difference between the Qishen Granule group and the fenofibrate group（P > 0.05）.Conclusion Qishen Granule can significantly improve myocardial fibrosis in rats with heart failure after myocardial infarction

and is equivalent to fenofibrate

and its mechanism may be related to the inhibition of TGF-βand Wnt pathway effect.