[Enhancement of fibroblast growth promoting activity of human blood after its irradiation in vivo (transcutaneously) and in vitro with visible and infrared polarized light].

Visible and infrared (IR) irradiation of laser and non-laser sources has a pronounced wound-healing effect promoting tissue repair without hyperproduction of connective tissue elements. This effect develops as a consequence of local and systemic light effects, but many aspects of their mechanism have been yet unclear. In the present work, we have shown that in 0.5 h after irradiation of a small area of the volunteers' body surface with polychromatic visible + IR light (400-3400 nm, 95% polarization, 12 J/cm2) the amounts of PDGF and TGF-beta 1 in the blood serum increase, on average, by 20 and 43%, respectively. This effect is preserved for at least 24 h to be recorded only in volunteers with the initially normal and decreased levels of the growth factors; the initially elevated content of PDGF-AB decreases. Addition of such a plasma (2.5%) to the nutrient medium of primary cultures of human embryonal fibroblasts stimulates cell proliferation, on average, by 10 and 17%, but only in the case if the initial growth-promoting (GP) blood activity was low. Similar changes occur in parallel experiments following irradiation of blood samples of the same volunteers in vitro, as well as at mixing irradiated and non-irradiated autologous blood at the ratio 1:10 (v/v), i.e. at modeling a situation in the vascular bed, when the transcutaneously photomodified blood contacts with the rest of its volume. Similar changes in the blood GP activity under conditions in vitro were recorded as well after 4-9 daily phototherapy sessions. This allows us to suggest that changes in GP activity of circulating blood of the irradiated volunteers may be, to a large extent, the consequence of effect exerted on the blood by small amounts of transcutaneously photomodified blood. The obtained results are discussed in terms of light effect on wound healing and scar tissue formation, with regard to the authors' previous data on much higher GP of the irradiated blood in respect to keratinocytes, the fast decrease in proinflammatory cytokine levels, and the increase in IFN-gamma content.