Research Paper Volume 8, Issue 12 pp 3400—3418

Figure 1. Oxidative stress induces intracellular calcium increase. hMESCs were treated with 200 µM H₂O₂ for 1 h and intracellular calcium levels were determined using Fluo-3 imaging techniques. (a) Time course of the relevant increase of [Ca²⁺]_i during 1 h H₂O₂ treatment in Ca²⁺-containing solution. Number of cells = 24. (b) Histogram, based on the data from (a), reflecting the relevant values of [Ca²⁺]_i on 2 min in control and on 60 min after H₂O₂ addition. (c) Time course of the relevant increase of [Ca²⁺]_i during 1 h H₂O₂ treatment in Ca²⁺-free solution containing 4mM EGTA. Number of cells = 28. (d) Histogram, based on the data from (c), reflecting relevant values of [Ca²⁺]_i in Ca²⁺-free basic solution on 2 min in control, on 5 min of EGTA action and on 60 min of H₂O₂ action. (e) Confocal images of hMESCs loaded with Fluo-3AM on 2 min of control, on 60 min of H₂O₂ action in Ca²⁺-containing solution and on 60 min of H₂O₂ action in Ca²⁺-free solution with EGTA. Scale bar is 100 µm and valid for all images. Values are M ± Std.Er. *** p<0.0001 by Mann-Whitney test. Application intervals and duration are marked with black lines above the graphs. Ctr – untreated cells. Representative results of three independent experiments are shown.