Figure 1. Effects of stretch on eNOS activation and NO production.

(A) HUVECs were subjected to 50% stretch for the times indicated (0, 2, 5, 15, 30, 60 and 120 min). Phosphorylation of eNOS in cell lysates was analyzed by immunoblotting with phospho-eNOS (Ser¹¹⁷⁷). The same blot was stripped and re-probed with antibody detecting total eNOS to monitor the equal loading of samples (upper), and the quantitative analysis of Ser¹¹⁷⁷ phosphorylation for eNOS was normalized by arbitrarily setting the density of control cells (time = 0) to 1.0 (lower). (B) Upper: Western blots of phospho-eNOS (Ser¹¹⁷⁷) in HUVECs stretched to the indicated magnitudes for 15 min. Lower: quantitative analysis of Ser¹¹⁷⁷ phosphorylation of eNOS. (C) DAF-FM staining was performed to detect NO release under continuous stretch (time = 15 min) and 1 mM L-NAME (a NOS inhibitor) was used to pre-treat HUVECs for 1 h. (D) Quantitative analysis of NO release under continuous stretch. Results are representative of 3 individual experiments and expressed as mean ± S.D. (n = 4). *p<0.05; **p<0.01; N.S., not significant.