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Fig. 2 | BMC Anesthesiology

Fig. 2

From: The antioxidant N-acetyl cysteine suppresses lidocaine-induced intracellular reactive oxygen species production and cell death in neuronal SH-SY5Y cells

Fig. 2

Critical involvement of mitochondria in lidocaine-induced cell death. HeLa cells and EB8 cells (HeLa cells lacking mitochondrial DNA) were exposed to the indicated concentrations of lidocaine (0, 0.1, 1, 4, or 10 mM) for 24 h. a Graphic depiction of the levels of caspase-3/7 activity in each treatment group, as determined using an Apo-ONE Homogeneous Caspase-3/7 Assay Kit™ (n = 4). b Treated and untreated cells were harvested, and the levels of cell death were analyzed by flow cytometry (n = 4). The ratio with propidium iodide (PI)- or annexin V-positive cells [(Q1 + Q2 + Q4)/(Q1 + Q2 + Q3 + Q4)] were indicated as dead cells (Additional file 1: Figure S1). c Graphic depiction of the oxygen consumption rate (OCR) in untreated SH-SY5Y cells and cells treated with lidocaine (0.1, 1, 4, or 10 mM), rotenone (100 nM), or carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP) (50 nM). Values are presented as ratios of OCR compared to that in the control (without lidocaine treatment) group (n = 4). d and e Graphic depiction of the levels of cell viability among SH-SY5Y cells treated with mitochondrial ETC inhibitors. Cells were treated with 1 mM lidocaine and either 100 nM rotenone, 2.5 μg/ml oligomycin, or 4 μM antimycin A, and subjected to (d) MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] assay (n = 3) or (e) caspase-3/7 activity assay (n = 3) analysis. f Graphic depiction of reactive oxygen species (ROS) production in SH-SY5Y cells exposed to 1 mM lidocaine in the presence or absence of 100 nM rotenone, 2.5 μg/ml oligomycin and 4 μM antimycin A for 6 h (n = 3). Data depict the ratio of ROS production in treated cells compared to that in the untreated control group. All data were expressed as means ± standard deviations (SD). Differences between results were evaluated by two-way analysis of variance (ANOVA) (a, b, e and f) followed by Dunnett’s test for multiple comparisons in each group or one-way ANOVA (c and d), followed by Dunnett’s test for multiple comparisons. #p < 0.05 compared with the control treatment population in the same group

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