Fig. 7.

Cx43 HCs mediate glutathione uptake and protect cells against oxidative stress. (A) Cells pre-treated with Cx43E2 antibody for 30 min were incubated 1 mM GSH for 20 min before treatment with H₂O₂ or UVB radiation. The cells were then incubated with fluorescent Thioltracker™ and the intracellular GSH level was quantified by measuring fluorescence intensity. At least three microphotographs of fluorescence fields were taken under a 20X microscope (Keyence BZ-X710) using a GFP filter. Bar, 50 μm. The average pixel density of 30 random cells was measured by using NIH ImageJ software. (B) Cells pre-treated with Cx43E2 antibody for 30 min were incubated 1 mM GSH for 20 min before treatment with H₂O₂ or UVB radiation, and followed by incubation with the Dead Cell Apoptosis Kit with FITC–Annexin V and PI (Molecular Probes). The cells with positive signal were quantified and presented as a percentage of total counted cells. Apoptosis (left panel) was quantified by counting Annexin V⁺ cell population; Necrosis (right panel) was quantified by counting Annexin V⁻/PI⁺ cell population. The data are presented as the mean ± SEM. (n = 3). *, P < 0.05; ***, P < 0.001; ****, P < 0.0001 (Two-way ANOVA).