Failure of a helium-neon laser to affect components of wound healing in vitro.

The red light of a helium-neon (He-Ne) laser has been reported to stimulate wound healing and cell growth. To investigate the nature of its influence on wound healing we have studied seven components of the healing process in vitro: human skin fibroblast, epithelial and endothelial cell proliferation, cellular migration from skin explants, collagen lattice contraction, collagen synthesis and glycosaminoglycans (GAG) secretion. We used a 5 mW He-Ne laser emitting a I mm diameter beam of wavelength 633 nm. Cellular proliferation was not affected by irradiation three times a day for 3 days. There was no effect on cellular migration or on the rate of collagen lattice contraction. The rate of collagen synthesis, measured as the incorporation of 3H-proline into collagenase-sensitive protein, was no greater than that of controls and GAG secretion did not increase in the irradiated group. We have not found any significant effects of He-Ne irradiation.