Silica exposure increases nitric oxide (NO) production in rat alveolar type II cell fractions.
Castranova-V; Pailes-WH; Judy-JD; Huffman-LJ
FASEB J 1994 Mar; 8(4):A147
Alveolar type II epithelial (type II) cells play an important role in the pulmonary response to irritant challenges. Recent evidence suggests that these cells produce NO which may, in turn, participate in defense reactions in response to foreign substances. In the present study, we assessed whether the intratracheal (IT) instillation of silica might be associated with an increase in NO production by rat type II cells. Male rats received IT instillations of endotoxin-free saline or silica (10 mg/100 gBW). After 24 hrs, type II cell-enriched fractions were isolated from perfused/lavaged lungs by elastase/collagenase digestion and purified by centrifugal elutriation. Inducible NO synthase (iNOS) mRNA levels in freshly isolated type II cell fractions were evaluated using Northern blot analysis. Media nitrate and nitrite levels were indexed after a 20 hr incubation period of type II cells in culture. iNOS mRNA levels were elevated in the type IT cell fractions isolated from silica-treated rats compared to saline-controls. After culture, total media nitrate and nitrite levels were three-fold higher in silica vs saline-exposed type II cell fractions. These results suggest that NO synthase expression is induced in rat alveolar type II epithelial cells in response to an in vivo silica challenge.
Laboratory-animals; Animal-studies; Silicates; Silica-dusts; Pulmonary-system-disorders; Respiratory-irritants; Respiratory-system-disorders; Alveolar-cells; Lung-disorders; Lung-irritants; Lung-cells
The FASEB Journal. Experimental Biology '94, Anaheim, California, April 24-28, 1994