Expression of TNF-α mRNA in hypertrophic myocardium by pressure overload in rats

AIM: To observe the change of TNF-α mRNA in hypertrophic cardiac myocytes induced by pressure overload in rats and the effect of captopril. METHODS: Serum and heart were collected 42 days after the cardiac hypertrophy model made by pressure overload by abdomen aorta-constriction (AC). Hypertrophic parameter and the concentration of TNF-α in serum and left ventricle were determined by ELISA. TNF-α mRNA in cardiac myocytes was determined by in situ hybridization and analyze by ELIA image analysis system. The orientation of (TNF-α) mRNA in cardiac myocytes was also observed. RESULTS: Left ventricle hypertrophy was observed 42 days after operation. TNF-α mRNA in AC group elevated 98% compared to sham-operated group and descended 64.14% by captopril ((P0.01),) but did not descend to the normal level. The expression of TNF-α mRNA showed mostly in myocardial matrix by in situ hybridization. The level of expression was very low in sham-operation group and markedly enhanced after aorta-constriction, but it was decreased when treated by captopril. CONCLUSION: Endogenous TNF-α acts as an important adjustive factor in the pressure overload-induced cardiac hypertrophy and TNF-α mRNA increased in myocardial matrix may be activated by renin-angiotension system.