Figure 3. Effect of HIF-1α siRNA on hypoxia preconditioning protection. Bovine stromal cells were transfected with the 15 nM (hypo15uv) and 25 nM (hypo25uv) HIF-1α siRNA and non targeting siRNA control (labeled as hyposiCuv) for 6 h. Twenty-four hours later, cells were exposed to hypoxia for 4 h and then stressed with UV-irradiation for 2 min. Cells were stained with TUNEL 4 h after irradiation. Error bars represent the standard error of the mean (n=3). The asterisk indicates statistically different from control UV irradiation.