Colchicine Inhibits Elevations in Both Alveolar-Capiliary Membrane Permeability and Lavage Surfactant After Exposure of the Rat to Phosgene

Abstract

Colchicine diminishes neutrophil incursion into the lung after COCl₂ exposure and reduces lung injury as reflected by lavage protein. Potential sources of lavage protein after phosgene inhalation include the leakage of serum proteins and surfactant accumulation. Permeability characteristics of the alveolar-capillary membrane can be altered by an influx of neutrophils. We tested the hypothesis that colchicine diminishes the neutrophil influx and associated elevations in permeability of the alveolar-capillary membrane but does not affect lavage surfactant accumulation after COCl₂ exposure. Rats were treated with either colchicine or saline prior to COCl₂ at 0.5 ppm × 60 min. To measure membrane permeability, ¹²⁵I-labeled bovine serum albumin was injected via the tail vein immediately and 1 day after exposure. After 2 h, radioactivity of blood and lavage fluid was measured. Lavage surfactant was quantified as phospholipid immediately and 1 day after exposure. Permeability was elevated immediately but returned to normal values 1 day after inhalation. Phospholipid in the lavage fluid showed no immediate change but was increased 7 day after COCl₂ inhalation. Colchicine inhibited both the immediate rise in the permeability index and the elevation of phospholipid 1 day after exposure to phosgene. We conclude that colchicine inhibited elevations in both alveolar-capillary membrane permeability and lavage surfactant after exposure to phosgene.