Additional file 2: of Combined exposure of diesel exhaust particles and respirable Soufrière Hills volcanic ash causes a (pro-)inflammatory response in an in vitro multicellular epithelial tissue barrier model

Cell morphology and cytotoxicity of the triple cell co-culture exposed to different single exposure doses of volcanic ash. Confocal laser scanning microscopy (LSM) images show the F-actin cytoskeleton (red) and the nuclei (blue) of (a) control and cultures exposed to (b) 0.13 μg/cm2, (c) 0.21 μg/cm2, and (d) 0.26 μg/cm2 of respirable volcanic ash. Yellow arrows indicate cells undergoing cell division. Scale bars are 20 μm. Images were collected at magnification 63×. (e) Cytotoxicity as determined by the release of lactate dehydrogenase (LDH) from the triple cell co-culture following single exposure to 0.13 μg/cm2, 0.21 μg/cm2, and 0.26 μg/cm2 of respirable volcanic ash. Data are presented as fold increase relative to the negative control (cell culture medium only) ± standard error of the mean. Triton X-100 at 0.2% in phosphate buffered saline (PBS) acted as the positive assay control. LDH data shown are related to the following repetitions for each exposure: SEVA n = 4; negative and positive controls n = 8. (TIF 524 kb)