Pulmonary functional and morphological damage after exposure to tripoli dust

• Tripoli is a microcrystalline siliceous rock used in polishing and cosmetics.
• Description of the physical and chemical characteristics of the tripoli dust.
• Exposure of mice to Tripoli dust impaired lung mechanics and morphology.
• Granulomas with collagen fibers were found and quantified in the lung.
• Inflammatory interleukins were detected in the lung tissue.

Tripoli is a microcrystalline siliceous rock used to polish metals and precious stones. Its inhalation has been associated with increased prevalence of breathing complaints and pneumoconiosis. However, its acute human exposure has not been so far studied. We aimed at evaluating the putative mechanical, morphological, biochemical and inflammatory lung damage in mice acutely exposed to Tripoli dust. BALB/c mice were randomly assigned to 2 groups: In control group (CTRL, n = 6) animals received intratracheally (i.t.) 0.9% NaCl (50 μl), while Tripoli group (TRIP, n = 15) received 20 mg of Tripoli powder diluted in 50 μL of saline i.t. The experiments were done 15 days later. TRIP mice showed higher pulmonary mechanical impedance, polymorphonuclear cells, TNF-α, IL1-β and IL-6 than CTRL. TRIP presented granulomatous nodules containing collagenous fibers that occupied 35% of the lung tissue area. In conclusion, acute exposure to Tripoli dust triggered important lung damage in mice lungs that if found in human workers could trigger severe illness.