Enhanced interleukin 1 production by alveolar macrophages and increase in Ia-positive lung cells in silica-exposed rats.
Inhalation exposure to silica dust enhanced interleukin 1 (IL-1) production by alveolar macrophages (AM), which is attributable to an increase in Ia-positive lung cells. While the proportion of Ia-positive cells in lavaged bronchoalveolar cells (BAC) was much lower (0-3%) in unexposed control rats, about a third of the rats that inhaled silica showed higher proportions (8.0-18.5%); these were designated "Ia-high" exposed animals. The number of total cells, Ia-positive cells and lymphocytes in BAC was significantly increased (P less than 0.05, P less than 0.001, and P less than 0.001, respectively) in these "Ia-high" exposed animals, compared to the control animals. Adherent AM populations obtained from BAC preparations also contained significantly higher (P less than 0.001) proportions of Ia-positive cells in the "Ia-high" exposed animals. When these adherent AM cultures were stimulated with lipopolysaccharide, IL-1 activity of the culture supernatants was enhanced and was significantly higher (P less than 0.001) in the "Ia-high" exposed rats, compared to the control animals. These results indicate that silica-exposure can induce populational changes in lung cells and also activation of AM associated with the increase in Ia-positive cells.
D000818:Animals; D000949:Histocompatibility Antigens Class II / Q000032:analysis*; D007375:Interleukin-1 / Q000096:biosynthesis*; D008168:Lung / Q000032:analysis*; D008264:Macrophages / Q000378:metabolism*; D008297:Male; D011650:Pulmonary Alveoli / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012822:Silicon Dioxide / Q000633:toxicity*; D012829:Silicosis / Q000276:immunology; D007507:Therapeutic Irrigation
D000949:Histocompatibility Antigens Class II; D007375:Interleukin-1; D012822:Silicon Dioxide