Objective To study the expression of telomerase(TMA) in myocardial tissue of myocardial ischemia in rat. Methods Sixty Spraque-Dawley rats were randomly divided into A, B, C three groups, then each group was randomly divided into control group and testing group.Two myocardial ischemia groups were injected isoprenaline (8 mg/kg), and two control groups were injected distilled water (8 mg/kg) in abdominal cavity.For the last myocardial ischemia group the coronary artery was ligated.The histological and immunohistochemical method were used for observing cardiac structural changes,with HE staining,and changes of TMA in myocardial tissue after myocardial ischemia in rat.The TMA contents were measured by image analysis. ResultsCompared with the respective control group,the expression of TMA in the three myocardial ischemia groups increased obviously(P<0.05 or P<0.01).The TMA contents in the three myocardial ischemia groups measured by image analysis were increased obviously,and had a prominent significance in statistics.Conclusion The TMA expression of rat myocardial tissue was increased after cardiac ischemia.