Myocardial protective effect and its mechanism of leukocyte-depleted reperfusion in neonatal rabbit hearts.

Thirty-six isolated blood-perfused hearts from newborn rabbits (age range, birth to 2 days) were subjected to 2 hours of cold global ischemia (15 degrees C), with an initial infusion of cold crystalloid cardioplegic solution, followed by 30 minutes of reperfusion (37 degrees C). The hearts were divided into two groups: those reperfused with whole blood (n = 18) and those reperfused with leukocyte-depleted blood (n = 18) obtained by the passage of blood through a leukocyte removal filter. At 30 minutes of reperfusion, the group of hearts reperfused with leukocyte-depleted blood showed significantly higher percentages of recovery in terms of the left ventricular developed pressure, the maximum rate of increase of left ventricular pressure, the rate pressure product, coronary sinus flow, and the adenosine triphosphate content in myocardium than did the group of hearts reperfused with whole blood. The hearts reperfused with leukocyte-depleted blood also showed significantly lower levels of malondialdehyde, chemiluminescence in the coronary sinus effluent, and counts of intracapillary neutrophils in myocardium than did the group of hearts reperfused with whole blood. The ultrastructural semiquantitative assessment in the myocardium showed that the mitochondrial and endothelial cell damages after 30 minutes of reperfusion were significantly less in the hearts reperfused with leukocyte-depleted blood than those in the hearts reperfused with whole blood.(ABSTRACT TRUNCATED AT 250 WORDS)