Protection induced by a brief ischemic episode in the langendorff perfused rat heart

Abstract

Ischemic episodes lasting approximately 1 min may be associated with coronary angioplasty. We explored whether such episodes could induce myocardial protection against prolonged ischemic episodes in an ex vivo model. Protection afforded by pretreatment with a 1-min ischemic episode (ischemic preconditioning) against prolonged ischemia was investigated in the isolated rat heart. Left ventricular developed pressure (LVDP; LV systolic pressure-LV end-diastolic pressure), heart rate (HR), and enzyme leakage (lactate dehydrogenase) were indexes of protection. An increased recovery of LVDP x HR after 16 and 19 min of ischemia of 37% and 28%, respectively, paralleled by reduced enzyme leakage, was observed in preconditioned hearts after 10 min of reperfusion. However, the difference between preconditioned and control hearts was lost after 30 min of reperfusion. Ischemic episodes lasting approximately 1 min are not sufficient to initiate stable protection even if initial functional and metabolic indexes suggest a protective effect.