Effects of HIF-1α-siRNA on oxidative and antioxidative products in the presence or absence of TX in OGD/R-treated H9C2 cells. H9C2 cells were transfected with HIF-1α-siRNA or NS-siRNA for 6 h, and then treated with TX (10 µM) followed by OGD (6 h)/R (18 h) treatment. (A) Intracellular ROS generation was measured using a DCFH-DA assay and the fluorescence intensity was observed under a fluorescent microscope. (B) The DCFH-DA assay was quantitatively analyzed using a flow cytometer. The (C) MDA content, (D) SOD activity and (E) GSH-Px activity were measured using commercial kits. Data are presented as the mean ± SD (n=3). *P<0.05, **P<0.01 vs. NS-siRNA + control; #P<0.05, ##P<0.01 vs. NS-siRNA + OGD/R; &P<0.05 vs. NS-siRNA + TX + OGD/R group. OGD/R, oxygen-glucose deprivation and reoxygenation; siRNA, small interfering RNA; HIF-1α, hypoxia-inducible factor-1α; NS, non-specific; TX, troxerutin; ROS, reactive oxygen species; MDA, malonaldehyde; SOD, superoxide dismutase; GSH-Px, glutathione peroxidase; DCFH-DA, 2′,7′-dichlorodihydrofluorescein diacetate.