Objective: To discuss the protective effect of paeonol on ventricular remodeling in acute myocardial infarction (AMI) rats and to investigate its influence on Smad2

Smad3

Smad7 mRNA expression of TGF-β/Smads signaling pathway. Method: In vivo model of AMI was made using the left anterior descending coronary branch ligation. The rats were randomly divided into the model group

the sham group

the low-

medium-and high-dose paeonol groups (8

12

16 mg · kg-1)

and the captopril group (10 mg · kg-1) based on ECG evaluation. The heart weight index and infarct size were measure after 4 weeks. The mRNA expression levels of Smad2

Smad3

Smad7 in myocardial tissues were detected using real-time quantitative (RT-qPCR) technique. Result: Compared with the model group

the myocardial infarct size was significantly reduced (P<0.05)

the heart weight index decreased (P<0.05) in all dose paeonol and captopril groups. Compared with the sham group

Smad2 and Smad3 mRNA expression levels were significantly higher

Smad7 expression level was lower in the model group (P<0.01). While

Smad2 and Smad3 mRNA expression levels decreased significantly

Smad7 expression level increased significantly in all dose paeonol groups (P<0.01). Conclusion: Paeonol has anti-myocardial fibrosis effect in AMI rats. Its mechanism may be related to increasing the Smad7 mRNA expression of TGF-β1 inhibitory signaling protein

and down-regulating the Smad2 and Smad7 mRNA expressions of TGF-β receptor signaling protein.