Abstract 2356: Effect of Age on Ischemia-Reperfusion Consequences in Mice
Aim Age-related changes in the mouse heart after ischemia-reperfusion (IR) have not been characterized in vivo. To test the hypothesis that senescence was associated with an increased susceptibility to myocardial injury after ischemia/reperfusion, we investigated by echocardiography the left ventricular (LV) function of adult and old mice.
Methods In young adult (2 months, n=11) and senescent (18 months, n=15) C57 BL/6 mice, 30 min of ischemia was performed by a left anterior descending coronary artery (LAD) ligation and was followed by 24 H of reperfusion . Echocardiography (13 MHz, Vivid 7, GE) was performed at baseline and at 24 hours after reperfusion to measure LV end-diastolic diameter (LVEDD), LV ejection fraction (LVEF, Simpson), anterior (AW) and posterior wall (PW) diastolic thickness and thickening. The area of risk (AR) size was assessed by blue dye and the infarct size (AN) and transmural extension of necrosis at mid LV level was assessed by TTC.
Results 4 senescent mice died during or just after the ischemia whereas none young mice died. At baseline, the 2 groups were similar on LVEF (77±3 in old and 79±4% in adult mice), AW thickening (44±2 vs. 45±4 %) and PW thickening (43±3 vs. 43±4%). Old mice had a concentric LV hypertrophy compared with the adult mice (wall thickness: 0.1±0.03 vs. 0.08 ±0.06 mm, p<0.05). After IR, LVEDD was significantly higher in old than in adult mice and LVEF was lower (table⇓, *: p<0.05). AN/AR was higher in old than adult mice (26±3 % versus 19±4%). In addition, the transmural extension of necrosis was significantly higher in the old mice (68±38 vs 39±24 % of the AW thickness, p=0.05).
Conclusion The senescent heart appears to be more susceptible to ischemia-reperfusion injury than the adult heart as demonstrated by the higher mortality, the increased infarct size and the lower LV function 24hours after IR.