Figure 2.

Luteolin prevented H₂O₂‐induced injury in H9c2 cardiomyocytes. Cardiomyocytes were treated with (A) luteolin (LUT) only (0.1–100 μM) for 24 h, or (B) increasing concentrations of H₂O₂ (50, 250, 500 and 1000 μM) for 2 h, and (C) luteolin (10–20 μM) followed by H₂O₂ (250 μM) for 2 h_. Cell viability was measured using the MTT assay. (D) The release of LDH at the end of the incubation with H₂O₂ was determined. (E) Cell morphology was observed after 2 h of H₂O₂ exposure. Abnormal cell morphology was induced by H₂O₂, whereas pretreatment with luteolin resulted in dose‐dependent protection from the H₂O₂‐induced morphological changes (×200, bar = 100 μm). Effects of luteolin on the protein levels of the peroxiredoxins (PRX), catalase and SOD1 in H₂O₂‐exposed H9c2 cells (F–I). Cells were cultured in six‐well plates until confluent, and the medium was replaced with serum‐free medium, with or without luteolin (10, 15 and 20 μM) for 2 h. The cells were then stimulated with 250 μM H₂O₂ for 2 h. Results were expressed as percentages of the control values (CON). Data shown are means ± SD for five independent experiments. Data in (G) and (I) were normalized against levels of β‐actin, which was used as a loading control. For calculation of relative changes in protein expression, values of individual samples were divided by the mean value of samples from the control group. Microscopic images are representative of five independent experiments. H₂O₂, simulated H₂O₂‐treated only. ^# P < 0.05, significantly different from control; *P < 0.05, significantly different from H₂O₂.