Figure 6. The counteracting effect of trolox. Cell viability assays with 3,(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide
(MTT) showed that 10 µM trolox significantly blunted the detrimental effect of light (1000 lux, 48 h) in serum-free medium
(white, unfilled bars) compared with cells incubated in normal medium in the dark (black bars;
Figure 6E). Moreover, analysis of DNA breakdown by TUNEL (
Figure 6A and
6B) or ROS formation (
Figure 6C and
6D) showed that the detrimental effect of light (
Figure 6A and
6C) was counteracted by inclusion in the medium of 10 µM trolox (B, D). Black arrows indicate TUNEL-positive cells. White arrows
mark red fluorescence in cells staining strongly for ROS (DHE labeling). The scale bar represents a distance of 20 μm. Statistical
significance, as indicated (*
p <0.05), was determined by one-way ANOVA followed by a post-hoc Bonferroni test which either compared cells in the light (without
serum) to controls, or compared cells in the light (without serum) with or without 10 μM trolox, as indicated in the figure.
Note that trolox had no significant effect on the viability measurement of cells incubated in the dark, in medium containing
serum.