FIG. 2.
Analysis of cytotoxicity and oxidative potential of six types of ambient PM. A, Cytotoxicity was analyzed by calculation of the number of nonviable cells present after the exposure to ambient PM particles measuring the amount of lactate dehydrogenase leaked from the cells. B and C, The differential expression of Cat and Hmox1 was determined by quantitative real-time PCR (qRT-PCR). The fold change data were calculated from the ΔΔCt values. All qRT-PCR reactions were conducted in triplicate and repeated twice. D, Induction of reactive oxygen species was analyzed by measuring a superoxide indicator DHE. Fifteen percent hydrogen peroxide (15% H2O2, 4.9 mol/l) was used as a positive control for 30 min at the end of 24-h exposure. E, Cellular bioenergetics was analyzed by measuring the mitochondrial function. Readings were taken after sequential addition of oligomycin (10 μM), carbonylcyanide 4-(trifluoromethoxy)phenylhydrazone (10 μM) and rotenone/antimycin A (10 μM). Oxygen consumption rates were calculated by the Seahorse XF96 software and represent an average of 3 measurements on 8 different wells. Asterisks (*) denotes significant (P < .05), (**) denotes significant (P < .01), and (***) denotes significant (P < .001) difference from control.