Figure 1. Effect of Cadmium on HIF-1α accumulation and hypoxia preconditioning protection. A: Cells were incubated under normoxia with 200 μM CoCl₂ (as a positive control), 5 μM CdCl₂ alone, hypoxia (0.5% O₂) alone, or hypoxia with CdCl₂ for 4 h. Whole cell lysates were collected immediately after treatment, separated on SDS-PAGE gel and blotted for HIF-1α. β-actin was detected as a loading control. B: Cells were pretreated with hypoxia with or without CdCl₂ for 4 h and irradiated 2 min with UV. Four hours after irradiation, cells were fixed and stained for TUNEL. Bar graph shows percentage of TUNEL positive cells in indicated groups. Error bars represent standard error of the mean (n=3); the asterisk indicates significantly different from UV control (p<0.05).