Alleviation of angiotensin II-induced ventricular hypertrophy in neonatal rat cardiomyocytes by endogenous intermedin

Aim To determine the interaction between endogenous IMD and cardiomyocyte hypertrophy.Method Myocyte hypertrophy was induced by treating the cells with angiotensin Ⅱ(Ang Ⅱ).Radioimmunoassay and Western blot analysis were used to determine IMD content in cultured neonatal rat ventricular myocytes,real-time PCR was used to measure mRNA levels of IMD and the IMD receptor components calcitonin receptor-like receptor(CRLR) and receptor activity modifying proteins(RAMPs),and the hypertrophic response was characterized by a significant increase in -Leu incorporation and BNP mRNA expression.Results Angiotensin Ⅱ led to an obvious decrease in the production,secretion,and mRNA expression of IMD and AngⅡ also influenced the mRNA expression of CRLR/RAMPs.In contrast,treatment with IMD antibody and specific antagonists of the IMD receptor potentiated the AngⅡ induced hypertrophic response in neonatal cardiomyocytes.Conclusion Endogenous IMD and its receptor system are involved in the onset and development of cardiac hypertrophy,which can be a potential therapeutic way for cardiac hypertrophy.