Fig. 1.

Dexamethasone induces superoxide generation in vascular cells and vessels.

(A) Human microvascular endothelial cells (HMEC-1) and pulmonary artery smooth muscle cells (PASMC) were treated with dexamethasone (Dex, 0.1–

1000 nM) for 4 h. The superoxide production rate was measured by EPR using CMH (n = 4–6; *p < 0.05 vs. Dex 0 nM; (1-β) = 1). (B) HMEC-1 and PASMC were treated with 10 nM dexamethasone (Dex) for increasing time periods. Superoxide production rate was measured as above (n = 4–6; *p < 0.05 vs. Dex 0 h; (1-β) = 1). (C) HMEC-1 were treated with 10 nM dexamethasone (Dex) for 4 h and superoxide production rate was measured in the presence of either polyethylene glycol (PEG) superoxide dismutase (SOD) or PEG catalase (cat) or both (SOD + cat) as above (n = 6; *p < 0.05 vs. Dex CTRCtr; (1-β) = 1). (D) HMEC-1 were treated with 10 nM dexamethasone (Dex) for 4 h and hydrogen peroxide levels were measured in the presence of PEG SOD (SOD) or PEG catalase (cat) or both (SOD + cat) by amplex red assay (n = 4; *p < 0.05 vs. Dex 0 h; (1-β) = 1). (E) Murine aortic rings (aortae) or pulmonary arteries (PA) were incubated with 10 nM dexamethasone (Dex) ex vivo. Superoxide production rate was measured as above (n = 4–6; *p < 0.05 vs. Dex 0 h; (1-β) = 1). Two-tailed Student's t-test was used in all cases.