Correction of regulatory molecules expression at the inflammation stage using photobiomodulation therapy in chronic wound modeling

Background. The search for effective treatments for chronic wounds continues. Photobiomodulation is a therapeutic approach that promotes cell differentiation, proliferation, and accelerated wound healing. The production of cytokines and growth factors determines the wound healing process, and their dysregulation can lead to wound chronicity. Therefore, by adjusting the levels of cytokines and growth factors, it is possible to influence the wound healing process. Purpose – correction of interleukin-8, vascular endothelial growth factor, and aminoterminal procollagen type III propeptide expression at the inflammation stage using photobiomodulation therapy in chronic wound modeling. Materials and Methods. The experiment involved 18 rats randomized into intact, control, and experimental groups. The rats of the control and experimental groups underwent surgical intervention to model the chronic wound. Photobiomodulation therapy was applied in the experimental group (wavelength 660 nm, energy density 1 J/cm2 , power 50 mW). After 72 hours, animals of all groups were euthanized. Interleukin-8, vascular endothelial growth factor, and amino-terminal propeptide of type III procollagen levels were determined using an enzyme-linked immunosorbent assay in the blood serum. Histologic analysis of wound samples was performed. Results. In animals whose wound defects were treated with photobiomodulation, an increase in serum levels of interleukin-8 and amino-terminal propeptide of type III procollagen (1.605 ± 0.117 pg/mL and 29.191 ± 0.905 pg/mL, respectively) was observed on the 3rd day of the experiment compared to those of the control group animals (1.302 ± 0.192 pg/mL and 13.054 ± 0.932 pg/mL, respectively, p < 0.05). Microscopically, after 3 days, signs of the beginning of the re-epithelialization process in the wounds of animals of both groups were noted. Wound cavities in animals of the control group were filled predominantly with fibrin fibers and elements of inflammation. In contrast, the experimental groupʼs animals were filled with young granulation tissue. Semi-quantitative histologic analysis showed differences in the cellular and extracellular composition of the wound contents. Conclusions. Photobiomodulation therapy promotes faster progression of the reparative process into the next phase of the healing process.