Toxicity Risks from Bacterial Endotoxin Inhalation.
NIOSH 1990 Nov:1489-1493
An investigation was conducted to determine if endotoxin inhalation may predispose workers to further pulmonary injury using an experimental model of adult respiratory distress syndrome. Hamsters were exposed to endotoxin inhalation for 6, 24, or 48 hours and then subjected to either no aerosol or the standard LPS inhalation challenge. Inhaled endotoxin caused a marked increase in total free lung cells recovered by lavage, reaching a maximum at 24 hours and returning to near normal by 48 hours. Polymorphonuclear granulocytes began to increase proportionately within hours, reaching a maximum at 6 hours. Pulmonary reactions were then compared from animals challenged with aerosolized saline suspensions of endotoxin or whole Enterobacter-agglomerans (E-agglomerans) bacteria for 1 hour. Inhalation of bacteria induced a significantly greater leukocyte infiltration into the lung. Most of this infiltrate consisted of alveolar macrophages and neutrophils. The ratio of alveolar macrophages was greater in the animals receiving whole cells, whereas the ratio of neutrophils was higher in the endotoxin exposed animals. Hamsters were given a standard aerosol of whole E-agglomerans cells for 30 minutes and allowed to rest for 6 hours to maximally develop pulmonary microlesions. One hour before this peak the animals were anesthetized and intravascularly injected with 0.2 milliliters of the same suspension used for aerosolization. Animals were sacrificed 1 hour later and bronchoalveolar lavage made for free lung cell analyses. Exposure to the complete regimen was characterized by a marked increase in erythrocytes and a relative decrease in the proportion of alveolar macrophages while the neutrophils proportionately increased.
Inhalation-studies; Respiratory-system-disorders; Pulmonary-function-tests; Laboratory-animals; Bacterial-dusts; In-vivo-study; Dust-inhalation; Lung-irritants;
Asthma and Chronic Obstructive Pulmonary Disease; Disease and Injury; Respiratory-system-disorders;
Proceedings of the VIIth International Pneumoconioses Conference