Pulmonary Function and Particle Deposition and Clearance in Rats After a 90-Day Exposure to Shale-Oil-Derived Jet Fuel JP-4

Abstract

A computerized, semiautomated plethysmograph system with a frequency response flat to 50 Hz was developed for pulmonary function evaluations in the rat. Before measuring the pulmonary effects of a 90-d exposure to shale-oil-derived JP-4, the sensitivity of this system was evaluated using papain-induced emphysema and bleomycin-induced fibrosis. The effects from these pulmonary insults were evaluated in tests of lung volumes, dynamic resistance and compliance, quasistatic compliance, partial and full forced vital capacities, carbon monoxide (CO) diffusion capacity, and closing volume. In addition, particle deposition and clearance were evaluated using ⁵¹Cr -labeled polystyrene latex microspheres. lntratracheally instilled bleomcyin (7 IU/kg) induced patchy interstitial fibrosis and generated a pattern of restrictive lung disease with significant changes in lung volumes and flow rates and significant differences in particle deposition and clearance. lntratracheally instilled papain (300 IU/kg) induced panlobular emphysema and generated a pattern of obstructive lung disease with significant changes in lung volumes, compliance, flow rates, gas distribution, CO diffusion, and mean linear intercept but showed no effects on particle deposition or clearance. Whereas previous reports found other hydrocarbon fuel exposures induced nasal inflammation and pulmonary irritation, a 90-d continuous exposure to 1000 mg/m³ shale-oil-derived JP-4 produced no significant effect histopathologically or in any measured pulmonary function, deposition, or clearance parameter.