Fig. 5

HIF-1α knockdown by siRNA affects the cytotoxicity and autophagy of HEK-293 cells. a Transfection efficacy was verified by western blot analysis. HIF-1α protein expression in HEK-293 cells transfected with control or HIF-1α siRNA for 24 h. b Cell viability in the absence or presence of HIF-1α siRNA in HEK-293 cells. c Quantification of apoptotic cells with Annexin V-stained cells using flow cytometry. d Quantification of AVOs with AO-stained cells transfected with control or HIF-1α siRNA using flow cytometry. The cells were transfected with control or HIF-1α siRNA for 24 h and treated with medium alone or 20 μg/ml ZnO NPs for 24 h. *p < 0.05, control siRNA + ZnO NPs versus HIF-1α siRNA + ZnO NPs