RhoA activation by calpeptin measured by G-LISA in hypoxic and normoxic hMSCs. The activation was performed in the same oxygen environment as the original cell culture. Cells were 80% to 90% confluent when treated with 0.1 mg/mL of calpeptin for 10 minutes, then lysed and the lysates were subjected to the G-LISA assay (activated MSC). The control cells were treated with the media, which did not contain calpeptin (non-activated MSC). The assay was performed in two dishes per experimental group; each experiment was repeated four times. Data are presented with the subtracted background (medium alone). Columns represent the average of four experiments combined (n = 8). The bars represent 1 SEM. × - P < 0.05, ×× - P < 0.01. MSC, mesenchymal stem cells; SEM, standard error of the mean.