EFFECT OF COTTON, HEMP, AND FLAX DUST EXTRACTS ON LUNG PERMEABILITY IN THE GUINEA-PIG

Byssinosis is an occupational lung disease in textile mill workers exp osed to the respirable dusts of cotton, hemp, and flax. This study inv estigated the influence of aqueous extracts from these dusts on overal l lung permeability in the guinea pig as an index of respiratory epith elial damage. Lung permeability was assessed by absorption into blood from the lung of inhaled technetium-99m diethylenetriamine penta-aceta te (Tc-DTPA) using gamma-scintigraphy. The half-life for Tc-DTPA absor ption (t(1/2)) was significantly reduced following a 4-week inhalation treatment with cotton, hemp, or flax dust extracts when compared to s aline control. There was at least a partial return to normal permeabil ity 7 days after stopping treatment. A single inhalation of extract di d not affect the t(1/2), but increased the number of neutrophils in br onchoalveolar lavage fluid 24 h postexposure. Neutrophil migration int o the airspaces therefore appeared to precede the increased lung perme ability. Long-term exposure was not associated with respiratory epithe lial shedding, suggesting that the increased permeability reflects a l oss of epithelial tight junction integrity arising from repeated expos ure to as yet undefined agents in these dusts.