Figure 1: The effects of low-power He-Ne laser irradiation on cell growth were assessed by trypan blue exclusion assay. (A) BEAS2B, (B) A549, and (C) H1299 cells were seeded with a density of 1-4×105 cells per well and were irradiated with 4.0 mW He-Ne laser radiations for various time courses and incubated for 1-3 days. Three independent experiments were performed. The data are presented as the mean ± SD. *P<0.05 compared with the untreated control group (0 min).