Enhancement of growth promoting activity of human blood on keratinocytes after its irradiation in vivo (transcutaneously) and in vitro with visible and infrared polarized light

To stimulate wound healing, current medicine uses various methods of phototherapy. The induced activation of proliferative processes in the wound occurs due to development of not only local, but also systemic processes, whose nature remains largely uninvestigated. The present work provides evidences that as early as 30 min after irradiation of a small area of the volunteer's body surface with polychromatic visible light + infrared polarized light (400-3400 nm, 95% of polarization) at a therapeutic dose (12 J/cm2), soluble factors appear in the circulating blood, which are able to stimulate proliferation of human keratinocytes in primary culture. A similar effect was also revealed after a direct blood irradiation. A proof is provided in favor of a hypothesis that a rapid rise of growth promoting activity of the entire circulating blood may be a consequence of transcutaneous photomodification of the small amount of light-modified blood in superficial skin vessels, and of the effect of such blood on its entire circulating volume. A possibility of a release into plasma of growth factors from blood cells and complexes with alpha 2-macroglobulin is discussed.