Nicotine and Cotinine Inhibit Catalase and Glutathione Reductase Activity Contributing to the Impaired Osteogenesis of SCP-1 Cells Exposed to Cigarette Smoke

Figure 2

CSE induces oxidative stress with an increase in ^⋅O₂ and GSH reduction in SCP-1. SCP-1 cells were exposed to 5% CSE, and intracellular ROS and GSH levels were measured with different fluorescent probes: (a) DCFH-DA assay was used to detect ^⋅O₂⁻, H₂O₂, HO^⋅, and ONOO⁻. To trap different ROS, SCP-1 cells were coincubated with 25 μM α-tocopherol (^⋅O₂ i), 10 mM sodium-pyruvate (H₂O₂i), 250 mM DMSO (HO^⋅i), or 100 μM uric acid (ONOO⁻ i); (b) DHE assay was used to detect ^⋅O₂⁻, and (c) Ellman assay was used to detect total GSH levels. Results were normalized to control SCP-1 cells (Crl). 0.01% H₂O₂ was used as positive control (a) or negative control (b) of the assays. Each experiment was conducted at least four times independently with triplicate. The statistical significance was determined by the Kruskal-Wallis H test followed by Dunn’s posttest. Data are represented as the mean ± SEM, and the significance was represented as , , and vs the control group.

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(b)

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