Objective:To investigate the effect of sildenafil citrate on left ventricular function and the levels of serum TGF-β1 and hydroxyproline(Hyp) content of myocardial tissue in rats with chronic heart failure (CHF). Methods:Female SD rats were randomly divided into the control group,the CHF group and the CHF + sildenafil treated group(n=7). The control rats derived from the normal rats; the CHF model rats were induced by intraperitoneal injection of doxorubicin; the CHF + sildenafil group were received the sildenafil 21 mg/(kg·d) gavage for 4 weeks after the success of CHF model rats. The CHF group and the control group rats were received placebo(1 ml distilled water) gavage for 4 weeks. After 10 weeks,the LVDd,LVDs,EF and FS of rats were measured by transthoracic echocardiography; the levels of serum TGF-β1 were tested by ELISA reagent kit and collagen content in myocardial tissue was determined by hydroxyproline assay. Results:Compared with the control group and the treatment group,the LVDs,LVDd,and the levels of serum TGF-β1 of the CHF group were significantly increased (P < 0.01) and the EF,FS were significantly decreased (P < 0.01); Hyp content in cardiac tissue of the CHF group was significant increased compared with the control group (P < 0.01) and the treatment group (P < 0.05). Conclusion:Sildenafil could improve the left ventricular function and reduce the deposition of collagen in the myocardial tissue and the levels of serum TGF-β1 in the rat models of CHF.