Figure 6
The protective effect of EGCG against the sub-toxic events induced by diesel-high exhaust in A549 cells. (A) Effects of EGCG on cell viability. Cells were exposed to increasing concentrations of EGCG for 48 h and cell survival was monitored by MTT assay. Data represent the means ± SD of three different experiments with triplicate determinations in each experiment. *p < 0.05 (B) EGCG reduced the cellular reactive oxygen species (ROS)-elevated by diesel exhaust exposure. Cells were exposed to 100 μM EGCG and 10 µg PM2.5/ml of the dichloromethane extracts (DEs) of diesel exhausts (alone or in combination). The generation of ROS was determined after 6-h exposure. Hydrogen peroxide and t-butyl hydroperoxide (t-BHP) were used as the positive exposure for ROS stimulation. (C) EGCG suppressed the potent biomarker-induction by DE of diesel-high exhaust. The mRNA levels of the exposure biomarkers were determined in cells exposed to the DE of the diesel-high exhaust with or without the co-exposure to EGCG for 6 and 48 h. In the determinations of ROS and mRNA levels, data represent the means ± SD of three different experiments with duplicate determinations. *p < 0.05 compared to the DMSO exposure; #p < 0.05 compared to the DE of diesel-high exhaust (Student’s t-test).
