Effects of an external exposure to 200 ppm methyl ethyl ketone on nasal mucosa in healthy volunteers

Abstract

Objectives: To investigate the effects of an acute exposure to 200 ppm methyl ethyl ketone on the nasal mucosa of healthy volunteers. Methods: Nineteen healthy non-smoking men were exposed to 200 ppm methyl ethyl ketone and to a sham exposure in an exposure chamber, using a cross-over design. Mucociliary transport time was determined with the saccharine test. Interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor-α (TNFα) were measured in nasal secretions. Subjective symptoms were assessed by questionnaire. Results: Mucociliary transport time was significantly higher (660 vs. 600 s (medians), P=0.01) after solvent exposure. Concentrations of IL-1β and IL-8 were insignificantly elevated after exposure (IL-1β: 83.8 pg/ml vs. 48.1 pg/ml, medians, P=0.11; IL-8: 14 471 pg/ml vs. 11 080 pg/ml, P=0.12), whereas those of IL-6 and TNFα remained unchanged. Subjects did not feel any irritation of nasal mucosa. Conclusion: Concentrations of organic solvents not exceeding their MAK values can cause subclinical rhinitis. The secretion of proinflammatory cytokines and impairment of mucociliary transport can explain the development of clinical rhinitis in highly exposed subjects.