RESUMEN
The purpose of this study was to determine the effects of chronic moderate and heavy ethanol consumption on myocardial ischemia/ reperfusion injury. Three groups (n = 18) of 6-month-old female Sprague-Dawley rats were fed a nutritionally balanced liquid diet. Control, moderate alcohol, and heavy alcohol groups consumed 0%, 20%, and 35% of their calories from ethanol, respectively. After 10 weeks of feeding, hearts were isolated and subjected to 21.5 min of ischemia alone, or 21.5 min of ischemia followed by 30 min reperfusion. Hearts were evaluated for hemodynamic characteristics and high-energy phosphate content. Hearts from animals exposed to moderate and heavy amounts of ethanol recovered significantly less (30.61% and 29.45%, respectively) of their preischemic cardiac external work than control hearts (65.52%). Postischemic diastolic stiffness was increased approximately 7-fold, and high-energy phosphate content, both creatine phosphate and adenosine triphosphate, decreased >25% by both chronic moderate and heavy ethanol consumption. In conclusion, both chronic moderate and heavy ethanol consumption exacerbate myocardial ischemia/reperfusion injury. The ethanol-induced reduction in postischemic energy status may be the mechanism of increased diastolic stiffness and subsequent reduced cardiac external work.
Asunto(s)
Alcoholismo/fisiopatología , Cardiomiopatía Alcohólica/fisiopatología , Contracción Miocárdica/efectos de los fármacos , Isquemia Miocárdica/fisiopatología , Daño por Reperfusión Miocárdica/fisiopatología , Adenosina Trifosfato/metabolismo , Animales , Diástole/efectos de los fármacos , Diástole/fisiología , Metabolismo Energético/efectos de los fármacos , Metabolismo Energético/fisiología , Femenino , Hemodinámica/efectos de los fármacos , Hemodinámica/fisiología , Contracción Miocárdica/fisiología , Fosfocreatina/metabolismo , Ratas , Ratas Sprague-DawleyRESUMEN
Growth hormone (GH) supplementation can increase the body weight of old rats, but the individual tissues affected were previously unidentified. Therefore, the masses of the heart, spleen, kidney, epididymal fat pads, and five skeletal muscles were assessed in male Fischer 344/Brown Norway rats (9, 20, 31, months) injected with recombinant human GH (0.7 mg/kg) or vehicle twice daily for 10 days. Muscle composition (fiber type, protein concentration, dry weight/wet weight ratio, citrate synthase activity) was also evaluated. Muscle mass was increased with GH treatment, and this increment was undiminished in old age. Fiber type, protein concentration, and dry weight/wet weight ratio were unaffected by GH. Citrate synthase activity declined in the plantaris and increased in the soleus with GH treatment. GH supplementation elevated heart and spleen mass, but not fat pad or kidney weight. The data demonstrate that the capacity for GH-induced hypertrophy of skeletal muscle, myocardium, and spleen is retained during old age.