Figure 1.

Effect of heat stress on apoptosis and apoptosis-associated proteins. HUVECs underwent an incubation period at 37°C (control) or a heat stress treatment at 43°C for 90 min prior to a recovery period at 37°C for 0, 2, 6 or 12 h. (A) After a 20 min probe with Hoechst 33342, cells were washed. Representative images obtained using a fluorescence microscope are presented. (B) Protein expression levels of Mcl-1 and Bax were detected in HUVECs by western blotting. (C) Caspase-3 enzymatic activity was measured in cell lysates. Data are presented as a relative to the control and represent the mean ± standard deviation of three separate experiments. **P<0.01 and ***P<0.001 vs. control. HUVECs, human umbilical vein endothelial cells; HS, heat stress; Cont, control; R, recovery time; Mcl-1, myeloid cell leukemia 1; Bax, B-cell lymphoma 2 associated X.