Abstract
Chronic exposure to industrial dust is known to cause diffuse lung diseases such as silicosis. We hypothesized that other common and inactive small particles may cause activation of alveolar macrophages and provide the trigger for lung injury or pulmonary fibrosis, via synthesis of chemoattractant for neutrophils such as leukotriene (LT) B4. SiO2 (1 to 5 μmφ) was used as positive control, latex beads (0.1, 0.5, 1.0, 3.0 μmφ) were used as inactive particles. Those particles were incubated with rat alveolar macrophages at 37°C for 90 min. The amount of generated LTB4, quantitated by reverse-phase HPLC, was 8.8±1.6 (control), 24±1.9 (SiO2) (p<0.05), 17±1.7 (0.1μmφ latex beads), 31±2.2 (0.5 pm4 latex beads) (p<0.05), 37±3.8 (1 μmφ latex beads) (p<0.05), 20±2.1 (3μmφ latex beads) (p<0.05) ng/2×106 cells. The concentration of LDH was also elevated in SiO2 and latex beads (1 and 3 μmφ) (p<0.05) .
These results may suggest that inhaled inactive particles induce diffuse lung disease via generation of LTB4.
