Effect of fasting and refeeding on the consequences of myocardial infarction in rats

Abstract

We investigated the effects of 48 hours (h)-fasting followed by permanent coronary artery occlusion and 48 h-refeeding on the infarct size; ejection fraction; plasma creatine kinase activity; and levels of IL1-β, CINC 2α/β and IL-6, triglycerides, glycogen and ATP in the left ventricle of adult rats. Permanent coronary artery occlusion was performed in ad libitum fed (fed/fed) and 2-days-fasted rats (fasted/re-fed). After infarction induction, both groups were re-fed for 48 h, and infarction area and ejection fraction were assessed using echocardiography. The levels of glycogen, triglyceride, ATP, and proinflammatory cytokines in the left ventricle, and the concentrations of glucose and free fatty acids in plasma were measured at the end of the 2-day fasting period. The infarct size was significantly smaller in the fasted/ re-fed group compared with the fed animals. This was accompanied by decreased plasma creatine kinase activity and improved ejection fraction. Fasting per se led to an increase in glycogen, ATP, CINC 2 α/β, interleukin (IL)-1β, and IL-6, and a decrease in triacylglycerol levels in the left ventricle; along with an increase in free fatty acid concentrations and a decrease in glucose levels in the plasma. This study indicates that 2-days-fasting followed by 48 h refeeding protected the heart from ischemia-induced injury, which may be related to the fasting-induced metabolic condition.