RESUMO
Heart failure [HF] is a major complication of virtually all forms of heart diseases. Recently neurohormonal mechanisms have been reported to play the main role in the pathogenesis of heart failure. The present study was designed to assess the possible protective effects of both growth hormone [GH] and insulin-like growth factor-1 [IGF-1] on post ischemia HF in rats. The present study was carried out on 50 male albino rats. Forty rats were subjected to coronary artery ligation and the other ten rats were sham-operated. Eight days after surgical intervention animals that survived were classified into four groups [n=10], first group served as control sham-operated group, the second group consisted of coronary ligated untreated rats, the third and fourth group consisted of coronary ligated rats that received GH and IGF-1 respectively for 6 weeks starting from post-ligation day 8. At the end of the study, each rat was weighed and blood samples were collected from tail vein. Plasma samples were used to determine TNF-alpha, aldosterone, IGF-1 and ANGII concentrations, then rats were sacrificed and the heart was rapidly excised, weighed and heart weight/body weight [HW/BW] ratio was calculated as an index of cardiac hypertrophy. After isolation of the left ventricular papillary muscles for determination of isometric force, left ventricular hydroxyproline [LVHPO] concentration [as a reflection of collagen content], was determined. It was found that non-treated coronary-ligated rats showed a significant increase in HW/BW ratio, plasma TNF alpha, aldosterone, ANGII concentration, and in LVHPO concentration. Also they showed a significant decrease in isometric force of left ventricular papillary muscles and a significant decrease in plasma IGF-1, as compared to sham-operated rats. Treatment of groups III and IV with GH and IGF1 resulted in significant change in HW/BW ratio, plasma aldosterone level and LVHPO concentration, nonsignificant increase in developed tension of isolated left ventricular papillary muscles, significant decrease in plasma TNF-alpha concentration and significant increase in plasma IGF-1 concentration as compared to group II. Also treatment of rats of group III with GH produced in significant change in plasma ANGII level while in group IV, IGF-1 produced a significant decrease in ANGII concentration as compared to group II