Preconditioning does not attenuate cardiac dysfunction after global ischaemia in the guinea‐pig

Abstract

Ischaemic preconditioning reduces infarct size, but the effects on cardiac function after global ischaemia are more controversial. Additionally, species differences may exist. The present study investigates the effects of preconditioning on cardiac performance in the globally ischaemic, Langendorff-perfused guinea-pig heart. Hearts were stabilized for 25 min, and divided into the following groups: (1) (n = 8) control perfusion for 16 min before 30-min global ischaemia and 30-min reperfusion, (2) (n = 7) two episodes of 3-min ischaemia and 5-min reperfusion before global ischaemia, (3) (n = 7) 5-min ischaemia and 10-min reperfusion before ischaemia, (4) (n = 8) control perfusion before 40-min ischaemia and 30-min reperfusion, (5) (n = 8) Preconditioning as group 2 before ischaemia as group 4, (6) (n = 9) Control perfusion before 50-min ischaemia and 30-min reperfusion, (7) (n = 10) Preconditioning as group 2 before ischaemia as group 6. A dose-dependent reduction of left ventricular systolic pressure, and increase of end-diastolic pressure was observed during reperfusion after 30-, 40- and 50-min ischaemia. Preconditioning did not influence these changes, nor did it attenuate the incidence of severe reperfusion arrhythmias or reduction of coronary flow. In conclusion, ischaemic preconditioning does not improve cardiac function during reperfusion of the globally ischaemic, isolated guinea-pig heart.

Mechanisms by Which Low-Intensity Ultrasound Improve Tolerance to Ischemia-Reperfusion Injury

“…Although ischemic preconditioning has been the target of increasing research over the last few years, the underlying mechanism of protection remains poorly understood (Vale 1998). Preconditioning is an endogenous phenomenon in which intermittent periods of ischemia or hypoxia, or even drugs or other mildly noxious stimuli, provides protection against longer periods of I/R to the organs such as heart, liver, intestine, stomach and brain.…”