[Establishment of a model of hydrogen peroxide-induced injury in pulmonary artery endothelium cells and relevant mechanisms of oxidative stress].

Objective: To establish a hydrogen peroxide (H(2)O(2)) induced injury model of pulmonary artery endothelial cells (PAECs) and explore the molecular mechanisms of oxidative stress on the structure and function of PAECs in this model. Methods: Human PAECs were treated with H(2)O(2) at different concentrations (25, 50, 100, 200, 400, 800, 1 600, 3 200, 6 400 μmol/L) for 4 and 24 h, respectively. The PAECs survival curve was obtained according to the cell viability measured by CCK-8 assay. The cell apoptosis of PAECs was detected by flow cytometry. The reactive oxygen species (ROS) generation and mitochondrial activity were measured using small molecule fluorescent probes. Proteins were extracted and the phosphorylation levels of signal molecules in PAECs were detected by Western blot assays. Results: (1) The effect of H(2)O(2) at various concentrations on cell viability of PAECs: cell viability of PAECs decreased in proportion to increasing concentration of H(2)O(2) after incubation for 4 h. The half maximal inhibitory concentration (IC(50)) of PAECs exposed to H(2)O(2) for 4 and 24 h were 397.00 and 488.77 μmol/L, respectively. (2) The effect of H(2)O(2) on cell apoptosis of PAECs: After H(2)O(2) incubation for 4 h, proportions of PAECs at late-apoptosis ((22.58±3.69) %) and necrotic stage( (11.86±4.27)%) were significantly higher than those of control PAECs at late-apoptosis stage( (3.41±1.44)%, P<0.01) and at necrotic stage ((1.94±1.15) % , P<0.05). The survival rate of PAECs post H(2)O(2) was dramatically lower than that of control PAECs ((7.98±3.21)% vs. (48.89±8.08)%, P<0.01). However, there is no statistical difference between both groups regarding to the early apoptosis. (3) The effect of H(2)O(2) on mitochondrial activity and ROS production of PAECs: the mitochondrial activity and ROS generation of PAECs treated by H(2)O(2) were significantly increased compared to those in control PAECs (P<0.01). (4) The effect of H(2)O(2) on signaling molecules in PAECs: there was a significant increase in phosphorylation level of Akt in PAECs incubated with H(2)O(2) for 30 minutes compared to that in control PAECs (P<0.01), while there was no significant difference in levels of Akt between H(2)O(2) treated PAECs and control PAECs. Phosphorylation level of JNK as well as p38 were also significantly upregulated in H(2)O(2) treated PAECs (P<0.01). Conclusion: H(2)O(2) at the concentration of 400 μmol/L could induce human PAECs injuries via the regulation of Akt and MAPK signaling pathways.