Lung endothelial and epithelial permeability after platelet-activating factor.
We investigated whether platelet-activating factor (PAF) increased epithelial or endothelial permeability in isolated-perfused rabbit lungs. PAF was either injected into the pulmonary artery or instilled into the airway of lungs perfused with Tyrode's solution containing 1% bovine serum albumin. The effect of adding neutrophils or platelets to the perfusate was also tested. Perfusion was maintained 20-40 min after adding PAF and then a fluid filtration coefficient (Kf) was determined to assess vascular permeability. At the end of each experiment, one lung was lavaged, and the lavagate protein concentration (BALP) was determined. Wet weight-to-dry weight ratios (W/D) were determined on the other lung. PAF added to the vascular space increased peak pulmonary arterial pressure (Ppa) from 13.5 +/- 3.1 (mean +/- SE) to 24.2 +/- 3.3 cmH2O (P less than 0.05). The effect was amplified by platelets [Ppa to 70.8 +/- 8.0 cmH2O (P less than 0.05)] but not by neutrophils [Ppa to 22.0 +/- 1.4 cmH2O (P less than 0.05)]. Minimal changes in Ppa were observed after instilling PAF into the airway. The Kf, W/D, and BALP of untreated lungs were not increased by injecting PAF into the vasculature or into the air space. The effect of PAF on Kf, W/D, and BALP was unaltered by adding platelets or neutrophils to the perfusate. PAF increases intravascular pressure (at a constant rate of perfusion) but does not increase epithelial or endothelial permeability in isolated-perfused rabbit lungs.
Medical Service, Veterans Administration Medical Center, Seattle, Washington.
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Bolin
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Martin
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Albert
D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000378:metabolism; D002199:Capillary Permeability / Q000187:drug effects*; D004730:Endothelium, Vascular / Q000378:metabolism*; D004848:Epithelium / Q000378:metabolism; D008168:Lung / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D009929:Organ Size / Q000187:drug effects; D010972:Platelet Activating Factor / Q000494:pharmacology*; D011506:Proteins / Q000378:metabolism; D011654:Pulmonary Edema / Q000503:physiopathology*; D011817:Rabbits
D010972:Platelet Activating Factor; D011506:Proteins