Study on protective effects of mouse intermedin against isoproterenol induced cardiomegaly / 重庆医学

ABSTRACT

Objective To investigate the pharmacological effect and mechanism of mouse intermedin (IMD)for antagonizing cardiac hypertrophy by using isoproterenol (ISO)induced mouse cardiomegaly model.Methods The mouse cardiomegaly model was constructed by small dose of ISO subcutaneous injection.The mouse blood dynamic indexes and heart weight/body weight rati-o were investigated.Then the cardiomyocyte cross-sectional area,apoptosis and cardiac tissue fibrosis were evaluated by using the cardiac tissue section.ANP,BNP,mRNA expression levels of endogenous IMD and its receptors system in cardiac tissues were de-tected by using real time fluorescence PCR method.Results Compared with the ISO induced mouse cardomegaly model group,the intraperitoneal injection of IMD significantly decreased the heart weight/body weight ratio and cardiomyocyte cross-sectional area increased by ISO treatment,cardiomegaly marker ANP and BNP mRNA level,cardiomyocyte apoptosis and cardiomyocyte fibrosis, improved the cardiac function,left ventricular pressure,maximal and minimal rate of LV pressure increase and decrease during the isovolumetric contraction phase,stroke volume,cardiac output and ejection fraction,but significantly decreased the left ventricle end-diastolic pressure.In addition,the ISO treatment significantly induced the expressions of endogenous IMD and its receptors in heart tissues.Conclusion ISO induces the expressions of endogenous IMD and its receptors in cardiac tissues,and exogenous IMD sup-plementation therapy realizes the pharmacological protective effect for antagonizing cardiomegaly by ISO activated IMD receptor system.