Research Paper Volume 8, Issue 5 pp 873—887

Figure 1. Impaired cardioprotection of insulin against MI/R injury in aged hearts. Young and aged rats were subjected to 30 minutes of ischemia by LAD ligation and followed by 2 hours of reperfusion with or without insulin treatment (60 U/L, intravenous infusion at 4 mL/kg per h for 2 h, beginning 5 min before reperfusion). (A) Left ventricular develop products were calculated by rate-pressure product (RPP) [heart rate (beats per minutes) × ventricular pressure (mmHg)]. (B and C) Maximal rate of rise of left ventricular pressure (±LVdP/dt_max). (D) Representative sections of myocardial infarction and the percent of infarct size after 4 hours reperfusion (*P < 0.05 vs. Young I/R; ^#P < 0.05 vs. Young I/R+Ins. Values are means ± S.E., n = 5 per group).