Endotoxin protection against oxygen-induced acute and chronic lung injury.
Small dosages of endotoxin (100--500 micrograms/kg) provide significant protection against the acute manifestations of pulmonary O2 toxicity and lethality. Ninety-seven percent of endotoxin-treated adult rats survived a 72-h exposure to greater than or equal to 95% O2 with mimimal lung changes, compared to 32% of control animals (P less than 0.01). Exposure to greater than or equal to 95% O2 for 7 days resulted in a 20% survival rate in untreated control rats vs. 98% survival in endotoxin-treated rats (P LESS THan 0.01). Histological evaluation of lung from survivors revealed substantially less collagen and reticular fiber deposition in the endotoxin-treated animal lungs. Endotoxin treatment was associated with increased activity of the protectant antioxidant enzyme systems of the lung in an apparent dose-response manner. Endotoxin's protective activity against O2 toxicity does not appear to depend on an initial toxic insult to the lung like with alpha-naphthylthiourea, oleic acid, or alloxan treatment. The data support a protective role for endotoxin against the acute and the more chronic manifestations of O2-induced pulmonary injury.
D000496:Alloxan / Q000627:therapeutic use; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004731:Endotoxins / Q000008:administration & dosage / Q000627:therapeutic use*; D006470:Hemorrhage / Q000517:prevention & control; D008171:Lung Diseases / Q000517:prevention & control*; D009829:Oleic Acids / Q000627:therapeutic use; D010100:Oxygen / Q000506:poisoning*; D011654:Pulmonary Edema / Q000517:prevention & control; D011658:Pulmonary Fibrosis / Q000517:prevention & control; D051381:Rats; D013890:Thiourea / Q000627:therapeutic use
D004731:Endotoxins; D009829:Oleic Acids; D000496:Alloxan; D013890:Thiourea; D010100:Oxygen