mRNA-induction and cytokine release during in vitro exposure of human nasal respiratory epithelia to methyl methacrylate

BackgroundMethyl methacrylate (MMA) has been reported to cause histopathological changes in rodent nasal epithelium after inhalation challenges. Data in humans are lacking.MethodsIn this in vitro design 22 primary cell cultures taken from inferior turbinate tissue of healthy individuals were exposed to MMA concentrations of 50 ppm (German MAK-value) and 200 ppm. mRNA expression and cytokine release of inflammatory mediators were quantified after 4 h and after 24 h. Controls were exposed to synthetic air. Q-PCR analysis was performed for TNF-α, IL-1β, IL-6, IL-8, MCP-1, GMCSF, Cox-1 and Cox-2. ELISA assays were performed from culture supernatants for TNF-α, IL-1β, IL-6, IL-8, MCP-1 and GMCSF.ResultsAcute inductions of mRNA after 4 h were observed for TNF-α, IL-1β, IL-6, IL-8 and MCP-1 at 50 ppm. ELISA analysis of the described parameters did not reveal any significant upregulations at both concentrations after both 4 h and 24 h.ConclusionsThe obtained data suggest that exposure of human respiratory epithelia in vitro to 50 ppm and to 200 ppm of MMA does not induce lasting upregulation of the inflammatory mediators measured in this study. The exposure limit of 50 ppm appears safe following these results obtained from human respiratory epithelia.