Neutrophils delay functional recovery of the post-hypoxic heart of the rabbit.
A postischemic contractile dysfunction termed myocardial stunning has been described in vivo and is attributed, in part, to the generation of oxygen-derived free radicals and the presence of neutrophils. An analogous contractile derangement occurs in the posthypoxic heart in vitro. This study determined the role of neutrophils in hypoxia/reoxygenation-induced cardiac dysfunction in the isolated buffer-perfused rabbit heart utilizing a recirculating system with or without neutrophils present. In control hearts perfused with a neutrophil-free buffer, reoxygenation after 20 min of hypoxia was associated with a slow recovery of contractility which returned to prehypoxic values by 30 to 45 min. Although perfusion with buffer-containing neutrophils did not affect the hypoxia-induced decrease in myocardial contractility, the recovery of contractile function during subsequent reoxygenation was significantly diminished (P less than .01 vs. control), remaining depressed by 30 to 35% at 45 min. The myocardial neutrophil content increased approximately 2-fold in response to hypoxia and reoxygenation, as assessed using 51Cr-labeled neutrophils. The deleterious effects of neutrophil perfusion on cardiac function could not be attributed to neutrophil-mediated plugging of coronary vessels or enhanced myocellular damage. These results support the concept that neutrophils contribute to the cardiac dysfunction described in this model.
Kraemer
R
R
Department of Pharmacology, New York Medical College, Valhalla.
Mullane
K M
KM
D000818:Animals; D006321:Heart / Q000503:physiopathology*; D000860:Hypoxia / Q000503:physiopathology*; D007975:Leukotriene B4 / Q000378:metabolism; D008297:Male; D009200:Myocardial Contraction; D015428:Myocardial Reperfusion Injury / Q000209:etiology; D009504:Neutrophils / Q000502:physiology*; D010972:Platelet Activating Factor / Q000494:pharmacology; D011817:Rabbits; D013481:Superoxides / Q000378:metabolism
D010972:Platelet Activating Factor; D013481:Superoxides; D007975:Leukotriene B4