Concentration Dependence of Pulmonary Responses of the Guinea Pig Animal Model Following Inhalation of Endotoxin Derived from Enterobacter agglomerans
V.A. Robinson, J. Milanowski, T. Meighan, M.N. Barger, M. Whitmer, D.G. Frazer, and V. Castranova
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ABSTRACT
Endotoxin was obtained from Enterobacter agglomerans, a gram-negative bacterium commonly associated with cotton dust, by the method of Boivin et al. (1). Guinea pigs were exposed for 3 hours to aerosols nebulized from solutions containing various concentrations of endotoxin (0.1 µg/ml to 3.3 mg/ml). Pulmonary responses 18 hours after exposure were as follows: 1) breathing rate, total lavagable cells, lymphocytes and red blood cells increased in a dose dependent manner, peaking at 1.0 mg/ml; 2) granulocytes increased by 74-fold at 1.0 )µg/ml before declining to a 34-fold increase at 3.3 mg/ml; 3) alveolar macrophages initially declined by 27% at 0.1 µg/ml endotoxin before increasing by 57% at 1.0 mg/ml; and 4) zymosan-stimulated superoxide release increased 102% at 3.3 mg/ml endotoxin. In conclusion, inhalation of E. agglomerans endotoxin resulted in pulmonary responses which were qualitatively similar to those seen with cotton dust.
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