PROTECTIVE EFFECT OF LOW LEVEL LASER THERAPY ON DORSAL SKIN FLAPS SURVIVAL: RELEVANCE TO CYTOKINES SECRETION.

Abstract

The loss of skin flaps (SF) due to tissue necrosis can be catastrophic, even with mortality, especially when there is exposure of large vessels or noble structures. This outcome occurs between 2 to 20% of the procedures performed. There is no currently adjuvant treatment that improves the survival of cutaneous flaps, without side effects or significant risks. Recent studies have sought to prove the efficiency of photobiomodulation (PBM) by means of Low Level Laser Therapy (LLLT) and present promising results for increased SF survival.OBJECTIVETo evaluate the effect of LLLT in dorsal skin flaps of mice in terms of tissue necrosis extent as well as biochemical analysis of pro and anti‐inflammatory cytokines.METHODSForty‐eighth Balb/C (20–25 g) male mice were randomly distributed into two groups with twenty‐four animals each; (1) control group that was not submitted to laser irradiation and (2) experimental group that was submitted to laser irradiation on the flap pedicle with a 660 nm wavelength, exposure radiant of 2.25 J/cm2 for a total time of 20 s/point. The treatment started immediately after performing the cranial base random skin flap (3× 1 cm dimension). The animals were euthanized after the evaluation of the percentage of necrosis area, blood and skin tissue was collected for analysis of cytokines and histology on 4th, 7th and 10th postoperative days. Results demonstrated that LLLT irradiation reduced the area of necrosis, significantly decreased IL‐1, IL‐6 and TNF‐α and increased IL‐10 cytokines compared to the non‐irradiated control group. In conclusion, LLLT may improve the healing of skin flaps by decreasing pro‐inflammatory cytokines and increasing the anti‐inflammatory IL‐10.Serum Interleukines after low level laser therapy (gray) versus control group (black). Significant decrease in pro‐inflamatories interleukines 1, 6 and tumor necrosis factor alfa and significant increase in anti‐inflamatory interleukin 10 after 4, 7 and 10 days post‐op.Figure 1