The effect of TRTS on cell proliferation of PC12 cells.

<p>(A–L) PC12 cells in cell growth medium were exposed to TRTS at two different temperatures for 18 h/day, or left untreated for 7 days. During TRTS, phase-contrast images were captured on day 0 (A, E, and I), day 3 (B, F, and J), day 5 (C, G, and K), and day 7 (D, H, and L). Phase-contrast images of PC12 cells during incubation without TRTS treatment (A–D); with TRTS at 39.5°C (E-H); or with TRTS at 42.0°C (I-L). Scale bar, 200 μm. (M) PC12 cells in the cell growth medium received TRTS at two different temperatures for 18 h/day, or were left untreated for 7 days, and the number of attached cells on the bottom of the plate was determined. The data represent the mean ± SD of four replicates. ††<i>P</i> < 0.01 vs. the day 0 controls with no stimulation. **<i>P</i> < 0.01. TRTS, temperature-controlled repeated thermal stimulation.