title: Effect of Pasteurella haemolytica-derived endotoxin on pulmonary structure and function in calves.
abstract: The role of endotoxin in the pathogenesis of acute pneumonic pasteurellosis is uncertain. Recently, we reported that Escherichia coli-derived endotoxin given by airway inoculation fails to induce lung injury in calves. Because Pasteurella haemolytica-derived endotoxin may differ substantially from E coli in its pathogenicity, we repeated these studies with Pasteurella endotoxin. Intratracheal inoculation of P haemolytica endotoxin caused hypoxemia and increased the alveolar-arterial oxygen differences without causing hypercarbia or changes in lung mechanical properties and volumes. In contrast, IV inoculation of endotoxin caused systemic hypotension, leukopenia, gas exchange impairment, increased total pulmonary resistance, and decreased dynamic compliance. Both routes of inoculation increased serum endotoxin concentrations and were associated with areas of pulmonary hemorrhage, edema, and acute inflammation. We concluded that P haemolytica-derived endotoxin is pathogenic by IV and airway routes of inoculation, and therefore differs from E coli endotoxin in its ability to induce lung lesions in calves.
authors.affiliation: Department of Pathology and Animal Health Diagnostic Laboratory, College of Veterinary Medicine, Michigan State University, East Lansing 48824-1314.
authors.forename: R F
authors.initials: RF
authors.lastname: Slocombe
authors.forename: M
authors.initials: M
authors.lastname: Mulks
authors.forename: C R
authors.initials: CR
authors.lastname: Killingsworth
authors.forename: F J
authors.initials: FJ
authors.lastname: Derksen
authors.forename: N E
authors.initials: NE
authors.lastname: Robinson
mesh_terms: D000818:Animals; D002417:Cattle; D004731:Endotoxins / Q000008:administration & dosage / Q000097:blood / Q000633:toxicity*; D000860:Hypoxia / Q000139:chemically induced / Q000662:veterinary; D007275:Injections, Intravenous / Q000662:veterinary; D008168:Lung / Q000187:drug effects* / Q000473:pathology / Q000502:physiology; D010325:Pasteurella; D012129:Respiratory Function Tests; D014132:Trachea / Q000187:drug effects / Q000473:pathology / Q000502:physiology
chemical_list: D004731:Endotoxins