PULMONARY VASCULAR-RESPONSE TO ENDOTOXIN IN NORMAL AND LYMPHOCYTE DEPLETED SHEEP

  • 1 January 1979
    • journal article
    • research article
    • Vol. 6  (1) , 13-21
Abstract
The cardiopulmonary effects of i.v. administered Escherichia coli endotoxin [etox] were studied in unanesthetized sheep. One group of animals was depleted of circulating T[thymus-derived]-lymphocytes while a non-depleted group served as control. T-lymphocyte depletion was accomplished by chronic thoracic duct drainage of lymph, removal of lymphocytes by continuous flow centrifugation and return of the cell-free lymph i.v. The T-lymphocyte depleted sheep demonstrated markedly obtunded increases in pulmonary arterial pressure and pulmonary vascular resistance following etox when compared to the effects of the lipopolysaccharide in control animals. The lymphocyte depleted group showed a significant augmentation of myocardial contractility which occurred at the same time as marked systemic hypotension. This period of extreme hypotension following etox may be accompanied by a reflex increase in the activity of the sympathetic nervous system. The control sheep, although equally hypotensive at this time, did not demonstrate a significant increase in myocardial contractility from the pre-etox value. T-lymphocytes may mediate some of the pathophysiological effects of bacterial etox on the cardiovascular system.