Ethylene glycol potentiated didecyldimethylammonium chloride toxicity in human bronchial epithelial cells

Didecyldimethylammonium chloride (DDAC) is an antimicrobial agent used as a preservative in household products. DDAC is toxic in human lung cells and in mouse lung. Aerosol products that contain DDAC often include ethylene glycol (EG) as a solvent; no safety information is available for respiratory toxicity of this combination (DDAC and EG). Human bronchial epithelial cells (BEAS-2B) were exposed (24 h) to DDAC and EG, separately or together. DDAC showed concentration-dependent cytotoxicity. EG did not affect cell viability. Compared to DDAC alone, EG and DDAC together enhanced mitochondrial damage and cell membrane disruption. Increased reactive oxygen species and decreased glutathione levels were seen in cells treated with the combination. Intracellular DDAC concentrations were elevated in the presence of EG. EG potentiated DDAC toxicity in lung cells by inducing oxidative stress through enhanced cellular uptake of DDAC. The use of these chemicals together in spray-type products should be carefully considered.