Fig. 4.

Free radical scavenger Tempol attenuates DHA-induced oxidative stress and UPR and improves cell proliferation. (A) Cells were loaded with 10 μM H₂DCFDA for 30 min followed by exposure to veh or DHA (100 μM) for indicated time periods up to 5 h, followed by flow cytometry. For the 24-h time point cells were incubated with veh or DHA for 23.5 h and then loaded with H₂DCFDA for 30 min in the presence of veh or DHA, followed by flow cytometry. (B) Cells were preincubated with Tempol (150 μM) or veh (DMSO) for 2 h (90 min before loading and during 30-min loading with H₂DCFDA). Thereafter, the cells were exposed to DHA in the presence or absence of Tempol for 3 h, followed by ROS measurement. (C) [³H]Thymidine incorporation in veh- or DHA-treated hPASMCs in the absence and presence of Tempol. (D) Representative Western blot of cyclin D1 protein expression in veh- or DHA-treated hPASMCs in the presence and absence of Tempol. (E) Representative Western blot of phosphorylated eIF2α in veh- or DHA-treated hPASMCs in the presence and absence of Tempol. Total eIF2α served as loading control. Data are given as means ± SEM of at least five independent experiments. *P < 0.05.