Effect of photobiomodulation therapy on regulating reparative processes of chronic wounds at the inflammation stage

Chronic wounds remain a major burden for patients and healthcare systems worldwide. Photobiomodulation therapy has demonstrated effectiveness as a physical method to support wound healing.

To assess whether photobiomodulation, applied with specific parameters, can modulate the inflammatory microenvironment of chronic wounds by examining its effects on pro and antiinflammatory cytokines, key growth factors, reactive oxygen species levels, and platelet aggregation, integrating these results with histopathological findings.

Eighteen rats were randomized into "intact", "control", and "experimental" groups. Chronic wounds were induced in control and experimental groups, with the latter receiving photobiomodulation therapy. Animals were euthanized 3 days postsurgery. Serum levels of reactive oxygen species (ROS), IL-1β, IL4, IL6, IL10, TNFα, bFGF, and TGF-β1 were measured via ELISA. Platelet aggregation assays and histological examinations were conducted.

On day 3, photobiomodulation increased ROS levels in the experimental group by 1.24fold compared with controls and by 1.23fold compared with intact rats. Photobiomodulation reduced IL4 levels by 1.58fold and decreased IL6 levels twofold relative to controls. While IL6 increased in control animals compared with intact rats, photobiomodulation reduced IL6 below intact levels. No significant differences were observed for IL1-β, IL10, TNFα, bFGF, or TGF-β1. Photobiomodulation was associated with reduced platelet aggregation during the inflammatory phase. Histological analysis revealed fewer macrophages and polymorphonuclear leukocytes and a higher number of fibroblasts in photobiomodulationtreated wounds.

Photobiomodulation therapy positively influences chronic wound healing by beneficially modulating inflammatory processes and promoting a more favorable tissue repair environment.