Photobiomodulation associated with lipid nanoparticles and hyaluronic acid accelerate the healing of excisional wounds.

<b>Objectives:</b> This article aimed to investigate the effects of the association between photobiomodulation and hyaluronic acid incorporated in lipid nanoparticles in an epithelial lesion model in inflammatory parameters and oxidative stress. <b>Methods:</b> Eighty Wistar rats were randomly assigned to the following groups: epithelial lesion group (EL); EL+PBM; EL+HA; EL+SLNs; EL+SLNs-HA; EL+PBM+HA; EL+PBM+SLNs; EL+PBM+SLNs-HA. The animals were anesthetized with 4% isofluorane after shaving and induced to an epithelial lesion. Topical treatment with a gel containing HA (0.9%) and/or SLNs (10 mg/mL) and with laser irradiation occurred daily for 1 week. <b>Results:</b> The results showed an increase in wound contraction on the seventh day in the LE + LBM + AH-NPL group, a reduction in pro-inflammatory cytokines (IL-6, IL-1β, and TNF-α), an increase in anti-inflammatory cytokines (IL- 4 and IL-10) and TGF-β. The levels of pro-inflammatory cytokine IL-4 and TGF-β also showed an increase in the LE + NPL-AH, LE + FBM + AH, LE + FBM + NPL and LE + FBM + NPL-AH groups. Regarding oxidative stress parameters, the levels of DCF and nitrite decreased in the combined therapy group when compared to the control group, as well as oxidative damage (carbonyl and sulfhydryl). In the antioxidant defense, there was an increase in GSH and SOD in the combination therapy group. Histological analysis showed a reduction in inflammatory infiltrate in the combination therapy group. The number of fibroblasts and the compaction of collagen fibers did not obtain significant responses. <b>Conclusions:</b> Results analyzed together showed that the combined therapy favored the repair process, and that studies can be carried out to enhance the histological analysis therapy favored the tissue repair process and that studies can be carried out to enhance the histological analysis.