Changes in the expression of endothelin system in rats with chronic heart failing

AIM: To study the changes of endothelin system during chronic heart failure (CHF) and imply the relationship between endothelin system and the course of CHF by observing the mRNA expression of endothelin receptors (ET_AR and ET_BR) and PreproET₁ in early stage and later stage of CHF caused by left coronary artery ligation. METHODS: The mRNA expression of ET_A, ET_B receptors and PreproET₁ were detected by RT-PCR technique. The plasma concentrations of ET₁ and ANP were determined by RIA method. RESULTS: The plasma concentrations of ET₁ and ANP, and the mRNA expression of ET receptors and PreproET₁ in the lefe ventricle increased significantly in early stage (myocardial infarction 10 d). While the plasma concentrations of ET₁ and ANP in later stage (myocardial infarction 70 d) were higher than those in the early stage. However, the mRNA expression of ET_AR, ET_BR and PreproET₁ decreased significantly. The mRNA expression of ET_AR in myocardial infarction (MI) 70 d rats had no difference with those in sham-operated rats and the mRNA expression of ET_BR and PreproET₁ in MI 70 d rats was lower significantly than those in MI 10 d rats, but significantly higher than those in sham-operated rats. CONCLUSION: The changes of ET receptors and PreproET₁ mRNA expression are involved in the cardiac function modulation during the different stages in chronic heart failure.