Abstract:

Abstract:Objective To explore the  effects of irbesartan on exrpession of periostin in  myocardium  tissue of  the viral myocarditis (VMC) mice  in chronic phase and myocardial fibrosis,and to clarify the possible mechanism of its antimyocardial fibrosis.Methods The models of VMC in chronic phase were founded by injecting coxsackie virus B3(CVB3) solution into 40 BALA/c mice. 21 VMC mice were divided into model group（n=11）and irbesartan group（n=10）.And at the same time, 10 BALA/C mice were used as control group.The mice in model group and control group were fed with water (1 mL?d-1),and the mice in irbesartan group were fed with irbesartan at a dose of 50 mg?kg-1?d-1.After 60 d,the levels of left ventricular end-diastolic dimension (LVEDd),left ventricular end-systolic dimension (LVEDs) and left ventricular fractional shortening (FS) of the mice in 3 groups were examined;the concentrations  of AngⅡ in the serum of the mice in various groups were detected by ELISA method;the myocardium tissue of mice were stained by MASSON and cardiac collagen volume fraction(CVF) was accounted.At the same time,the contents of periostin mRNA and TGF-β1 mRNA in myocardium tissue of mice were detected by RT-PCR method.Results Compared with control group,the levels of  LVEDd and LVEDs were  increased （P<0.01），and the level of FS was decreased （P<0.01） in model group;the levels of serum Ang Ⅱ,CVF,TGF-β1 mRNA,and periostin mRNA were increased （P<0.01）in model group.Compared with model group,the levels of LVEDd  and  LVEDs of the mice in irbesartan group were obviously decreased（P<0.05），and the level of FS was increased（P<0.05）.There was no significant difference of the levels of serum Ang Ⅱ between irbesartan group and model group（P>0.05),but the levels of CVF,TGF-β1 mRNA,and periostin mRNA of the mice in irbesartan group were obviously decreased compared with model group（P<0.05）.Conclusion Irbesartan can offer some protection to myocardial fibrosis inVMC mice. The  probable mechanisms may be acted through  inhibiting  the expression of TGF-β1 in myocardium tissue to reduce the expression of  periostin.

Key words: viral myocarditis, myocardial fibrosis, irbesartan, periostin