Aim To investigate the changes of matrix metalloproteinase-2 and 9(MMP-2,MMP-9)in rat cardiac hypertrophy,and the effects of Pentoxifylline(PTX)on it in a rat model.Methods Twenty-four male SD rats were randomly divided into control group,norepinephrine(model)group and norepinephrine + PTX(treated)group.The rat cardiac hypertrophy models were established by intraperitoneal injection of norepinephrine(NE)twice a day for 15 days.Extracellular matrix remodeling was evaluated by morphological examination,stained with Van-Gieson(VG).The content of hydroxyproline in the tissue of myocardium was measured.The protein expression of MMP-2 and MMP-9 were examined by immunohistochemical analysis.Results NE-induced hypertrophy and extracellular matrix remodeling predominantly occurred in the left ventricular,the expression of the collagen(1.929±0.514 mg/g vs 1.009±0.442 mg/g,p<0.01)elevated obviously;the average of the grave scale of protein expression of the MMP-2(131.1±9.8)and MMP-9(125.3±4.1)were lower than those of the control group obviously(p<0.01);After PTX treatment,the collagen(1.151±0.215 mg/g)was decreased and the average of the grave scale of protein expression of MMP-2(153.5±6.9)and MMP-9(149.5±5.3)were higher than those of the model group prominently(p<0.01).Conclusion Pentoxifylline can prevent the cardiac hypertrophy and extracellular matrix remodeling,which was associated with the attenuation of myocardial MMP-2 and MMP-9.