(A) Western blot analysis of Hsp90, Hsp70, and Hsp27 in human LECs immediately after exposure to RF field (SAR: 1, 2, 3, 4 W/kg) for 2 h. (B) Data of Hsp protein levels are representative of at least three independent experiments. The intensity of bands was quantitated by densitometry. Each data point represents the mean±SD (n = 3). *P < 0.05, compared with sham. HS: heat shock (positive control). (C) Effect of RF field on the phosphorylation of ERK1/2 in human LECs. The cell culture medium was not changed prior to irradiation. (D) Effect of RF field on the phosphorylation of JNK1/2 in human LECs. (E) Effect of RF field on the phosphorylation of p38 in human LECs. As a positive control, cells were stimulated with anisomycin (ANISO, 10 μg/ml) for 30 min. Ani: Anisomycin. In (C-E), cells were exposed to RF field at SARs of 2, 3, and 4 W/kg for 5, 15, 30, 60, and 120 min. The experiments were repeated three times.