Effects of low power 904 nm radiation on rat fibroblasts explanted and in vitro cultured

Abstract In this study, 904 nm radiation was used on rat fibroblasts, explanted and in vitro cultured, to verify the action of various factors on cell growth. Parameters which can modify the behaviour of cultured cells, including the pulse repetition rate and the intensity of the radiation, the distance between the source and the irradiated dishes, the daily duration of exposure and the length of treatment, were studied. The most effective values of the intensity and pulse repetition rate which stimulate cell growth were 3×10 −4 W m −2 and 1.6 kHz respectively; the best stimulation was obtained at a sample-source distance of 0.1 m. The duration of daily exposure had no significant effect, whereas the best stimulus of cell growth was obtained by extending the treatment to 12 days.