Fig. 1
HUVECs viability after 16-, 24- or 48-h exposure to 32 % O2, as evaluated by the trypan blue assay. The results were compared with those obtained at time 0 h (control). Results are expressed as mean ± SD of at least three experiments. Bars represent the percentage of viable treated cells (mean percentage) versus control. *P < 0.05 versus 0 h. °P < 0.05 versus cells exposed to mild hyperoxic conditions for 16 h. § P < 0.05 versus cells exposed to mild hyperoxic conditions for 24 h