Abstract: AIM: To explore the effect of diabetes on ventricular remodeling in non-infarcted areas after myocardial infarction in type II diabetic rats by comparing changes of cardiac hypertrophy (TGF-β1), proliferation differentiation (PCNA) and apoptosis (TUNEL). METHODS: Sprague Dawley (SD) rats were randomly divided into blank group, diabetic group, infarcted group and infarcted diabetic group. Samples were obtained from the infarcted diabetic rats in non-infarcted area. Using immunohistochemistry and computer image processing technique, TGF-β1, PCNA and TUNEL expressions were examined in different groups (blank, diabetic, infarcted, infarcted diabetic). RESULTS: After myocardial infarction, the positive rates of TUNEL, PCNA, TGF-β1 in non-infarcted areas in infarcted diabetic group were significantly higher than those in the blank group, diabetic group and infarcted group (P<0.01). Compared with the infarcted group, the positive rate of TUNEL in non-infarcted areas in diabetic group was significantly higher. CONCLUSION: Diabetes increased expressions of cardiac hypertrophy, proliferation and apoptosis in non-infarcted regions, which may be the pathophysiological basis of high morbidity of ventricular arrhythmia and high mortality after myocardial infarction in diabetes.