Tracing the leukocyte marker protein in lung fluids and lung-draining lymph nodes during endotoxemia in sheep.
Infusion of Escherichia coli endotoxin into sheep produces a form of acute lung injury that resembles the adult respiratory distress syndrome (ARDS). A large portion of the physiologic derangements produced by E. coli endotoxin in this model is thought to be granulocyte-dependent. We measured the level of L1, a granulocyte and monocyte marker protein, in various tissues and fluids after infusion of E. coli endotoxin into sheep. In an acute study, sheep received saline or 1.25 microgram/kg E. coli endotoxin dissolved in saline, or endotoxin after hydroxyurea-induced granulocytopenia. L1 was measured by radioimmunoassay in efferent lymph from the caudal mediastinal lymph node collected between 5 and 6 h after infusion. In addition, L1 was visualized in both lung-draining and extrapulmonary lymph nodes by indirect immunofluorescence. In a chronic study, sheep were prepared with lung lymph fistulas, and L1 was measured in draining pulmonary lymph, plasma, and bronchoalveolar lavage (BAL) fluid, serially, over a 24-h period after infusion. Mean L1 level in pulmonary lymph in the acute study was 6 times higher by absolute concentration, and 19 times higher when lymph flow rates were taken into account, in the sheep that received endotoxin than in saline-infused sheep or endotoxin-infused, granulocytopenic sheep. Fluorescence was greater in the outer cortical region adjacent to subcapsular, afferent sinuses of lung draining-lymph nodes of endotoxin-treated sheep than in the comparable nodes of saline-infused sheep and endotoxin-infused granulocytopenic sheep. In endotoxin-treated sheep, extrapulmonary lymph nodes were less reactive than lung-draining nodes.(ABSTRACT TRUNCATED AT 250 WORDS)
D000818:Animals; D000954:Antigens, Surface / Q000032:analysis* / Q000097:blood; D004731:Endotoxins; D004927:Escherichia coli Infections / Q000378:metabolism*; D005260:Female; D005402:Fistula; D005455:Fluorescent Antibody Technique; D006098:Granulocytes / Q000032:analysis; D007958:Leukocyte Count; D039841:Leukocyte L1 Antigen Complex; D008168:Lung / Q000032:analysis* / Q000502:physiology / Q000601:surgery; D008198:Lymph Nodes / Q000032:analysis* / Q000502:physiology / Q000601:surgery; D008297:Male; D012756:Sheep
D000954:Antigens, Surface; D004731:Endotoxins; D039841:Leukocyte L1 Antigen Complex