title: Role of size and surface area for pro-inflammatory responses to silica nanoparticles in epithelial lung cells: importance of exposure conditions.
abstract: The present study compared non-crystalline silica particles of nano (50nm)- and submicro (500nm)-size (Si50 and Si500) for the potential to induce cytokine responses in bronchial epithelial lung cells (BEAS-2B). The cell cultures were exposed to equal mass and surface area concentrations of the two particles in different exposure media; LHC-9 and DMEM:F12. The state of agglomeration was different in the two media; with marked agglomeration in LHC-9 and nearly no agglomeration in DMEM:F12. On a mass basis, Si50 was more potent than Si500 in inducing cytokine responses in both exposure media. In contrast, upon exposure to similar surface area concentrations, Si500 was more potent than Si50 in DMEM:F12. This might be due to different agglomeration/sedimentation properties of Si50 versus Si500 in the two media. However, influence of differences in particle reactivity or particle uptake cannot be excluded. The data indicated no qualitative changes in the cytokine gene-expression patterns induced by the two particles, suggesting effects through similar mechanisms. These aspects might be of importance for interpretation of in vitro studies of nanomaterials.
authors.affiliation: Division of Environmental Medicine, Norwegian Institute of Public Health, P.O. Box 4404, Nydalen N-0403, Oslo, Norway. Electronic address: tonje.skuland@fhi.no.
authors.forename: T
authors.initials: T
authors.lastname: Skuland
authors.affiliation: Division of Environmental Medicine, Norwegian Institute of Public Health, P.O. Box 4404, Nydalen N-0403, Oslo, Norway.
authors.forename: J
authors.initials: J
authors.lastname: Ovrevik
authors.affiliation: Division of Environmental Medicine, Norwegian Institute of Public Health, P.O. Box 4404, Nydalen N-0403, Oslo, Norway.
authors.forename: M
authors.initials: M
authors.lastname: Låg
authors.affiliation: Division of Environmental Medicine, Norwegian Institute of Public Health, P.O. Box 4404, Nydalen N-0403, Oslo, Norway.
authors.forename: M
authors.initials: M
authors.lastname: Refsnes
mesh_terms: D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003470:Culture Media; D016207:Cytokines / Q000096:biosynthesis / Q000235:genetics; D004563:Electrochemistry; D004847:Epithelial Cells / Q000187:drug effects*; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D015850:Interleukin-6 / Q000096:biosynthesis; D016209:Interleukin-8 / Q000096:biosynthesis; D008027:Light; D008168:Lung / Q000166:cytology*; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000633:toxicity*; D010316:Particle Size; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020545:Respiratory Mucosa / Q000187:drug effects*; D012542:Scattering, Radiation; D012822:Silicon Dioxide / Q000633:toxicity*; D013499:Surface Properties
chemical_list: D003470:Culture Media; D016207:Cytokines; D015850:Interleukin-6; D016209:Interleukin-8; D012333:RNA, Messenger; D012822:Silicon Dioxide
keywords: BEAS-2B; Cytokine gene arrays; Cytokine responses; Exposure conditions; Silica nanoparticles; Size and surface area