ARE DIABETIC HEARTS MORE RESISTANT TO ISCHEMIA-REPERFUSION INJURY

The present study was designed to investigate the cardiac impairment d uring ischemia/reperfusion injury in rats with streptozotocin-induced diabetes vs controls. Male rats were divided into three groups: contro ls, one-week diabetic rats (1wDM) and four-week diabetic rats (4wDM). In the isolated working heart, left ventricular developed pressure (LV DP), left ventricular end-diastolic pressure (LVEDP), and maximum posi tive and negative dP/dt were measured before ischemia and after 20 min of global ischemia followed by 30 min reperfusion. In the pre-ischemi c state, hearts of 4wDM showed a significant (p<0.05) depression of th e maximum positive and negative dP/dt compared with those of controls and 1wDM. There were no significant differences in LVDP and LVEDP amon g the three groups. The incidence of reperfusion-induced ventricular f ibrillation (VF) was 75% for controls, 15% for 1wDM rats, and 27% for 4wDM rats. In hearts without reperfusion-induced VF, there were no dif ferences in the three groups, between the pre- and post-ischemic value s in LVDP, LVEDP, and maximum positive and negative dP/dt. These findi ngs suggest that diabetic hearts exhibit no susceptibility to ischemia /reperfusion injury.