This study was carried out to investigate the effects of pentoxifylline and adenosine on the pulmonary injury induced by E. coli endotoxin. The counts of circulating neutrophils I peripheral blood and pulmonary sequestration of
neutrophils
after injection of endotoxin, endotoxin with pentoxifylline, or endotoxin with adenosine, additionally electron microscopy of the lungs were carried out.
To account the circulation neutrophils, six white rabbits were intravenously injected 4mg/kg of E. coli 026: B6 lipopolysaccharide, and then counted circulating neutrophils at 0, 1, 2, 4, and 8 hours after injections. Another six were injected
4mg/kg
of endotoxin simultaneously with 100mg/kg of pentoxifylline(40mg/kg at 0 hour and 20mg/kg at 1, 2, and 4 hours after first injection), then neutrophils were counted at 0, 1, 2, 4, and 8 hours after injection of the endotoxin, The six
were
injected 4mg/kg of endotoxin simultaneously with 50mg/kg of adenosine(20mg/kg at 0 hour and 10mg/kg at 1, 2, and 4 hours after first injection), also the neutrophils were counted at 1, 2, 4, and 8 hours after endotoxin injection.
Neutrophilic pulmonary sequestration was counted at 8 hours after injection of endotoxin, endotoxin with pentoxifylline, or endotoxin with adenosine. Electron microscopy of the lungs was carried out at 1, 4, and 8 hours after injections in
each
group.
@ES The results were as follows:
@EN The number or circulating neutrophils was markedly decreased at 1 hour after endotoxin injection and sustained until 8 hours after injection. In the pentoxifylline and adenosine injected groups, circulating neutrophils
were
decreased in number at 1 hour, however, nearly recovered at 8 hours after injections. Pulmonary sequestration of neutrophils was marked in endotoxin injected group. In contrast, endotoxin with pentoxifylline and endotoxin with
adenosine
injected groups demonstrated mild sequestration of the neutrophils. Ultrastructural changes of the lungs were swelling. formation of cytoplasmic projections, and seperation of the cytoplasm from the basement membrane in the endothelium,
sewlling of
type II pneumocytes, and interstitial edema appeared in pentoxifylline and adenosine injected groups.
According to the above results, it is concluded that pentoxifylline and adenosine inhibit pulmonary sequestration of the neutrophils in endotoxemia and suppress pulmonary injury induced by endotoxin.
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