Objectives To investigate the effects and possible mechanism of Kangxian Yixin Recipe（抗纤益心方） on myocardial fibrosis in dilated cardiomyopathy（DCM）. Methods Totally 100 rats were randomly divided into normal group（8 rats） and model making group（92 rats）. The DCM model was established by drinking the solution of furazolidone aqueous autonomously. Forty successful modeling rats were further randomly divided into model group

captopril group

Kangxian Yixin Recipe low

medium and high dose groups

with eight rats in each group. Kangxian Yixin Recipe low

medium and high dose group rats were administered with Kangxian Yixin Recipe by gavage at a dose of 0.9 g/（kg·d）

1.8 g/（kg·d）

and 3.6 g/（kg·d）

respectively; captopril 10.13 mg/（kg·d） by gavage was given to captopril group

while normal saline 5.3 ml/（kg·d） by gavage was given to the normal group and model group. After four weeks

the left ventricular end-diastolic diameter（LVEDD）

left ventricular end-systolic diameter（LVESD）

left ventricular ejection fraction（LVEF） and left ventricular fractional shortening（LVFS） levels were detected; the pathological changes of myocardial tissues was assessed; the protein and mRNA expression of alpha-smooth muscle actin（α-SMA）

type I collagen

β-catenin and peroxisome proliferators-activated receptor γ（PPARγ） were determined. Results Compared to the normal group

LVEDD and LVESD levels in the model group significantly increased

while LVEF and LVFS levels decreased（P<0.05）; the myocardial pathological damage was aggravating; the protein and mRNA expression of α-SMA

type I collagen and β-catenin increased

while the expression of PPARγ protein and mRNA decreased（P<0.05）. Compared to the model group

the LVEDD and LVESD levels were reduced

the LVEF and LVFS levels increased; the degree of myocardial pathologic fibrosis and the protein expression of α-SMA and type I collagen decreased in Kangxian Yixin Recipe medium and high dose groups and captopril group（P<0.05）; the expression of β-catenin protein and mRNA significantly decreased

while the expression of PPARγ protein and mRNA increased in Kangxian Yixin Recipe medium and high dose groups（P<0.05）. Compared to captopril group

Kangxian Yixin Recipe medium and high dose groups had lower expression levels of β-catenin protein and mRNA（P<0.05）

while no significant differences were found in LVEDD

LVESD

LVED

LVFS levels

and the protein and mRNA expression of type I collagen and PPARγ（P>0.05）. Compared to Kang-xian Yixin Recipe low dose group

there were lower LVEDD and LVESD levels

higher LVEF

LVFS levels and PPARγ mRNA expression in the medium and high dose groups

as well as lower expression of type I collagen protein in the high dose group（P<0.05）. The comparison between Kangxian Yixin Recipe medium dose and high dose group was not significantly different in all indicators（P>0.05）. Conclusion Kangxian Yixin Recipe can effectively improve the cardiac function of DCM rats

and inhibit ventricular remodeling and myocardial fibrosis; and the effect is better with medium and high doses. The mechanism may be related to the regulation of β-catenin/PPARγ pathway expression.