Influence of Laser (λ670 nm) and Dexamethasone on the Chronology of Cutaneous Repair

Objective: This study aimed to assess the effect of LLLT associated with and without dexamethasone on inflammation and wound healing in cutaneous surgical wounds. Background: Limited studies are directed at the possible interference of laser photobiomodulation on the formation of myofibroblasts, associated with an anti-inflammatory drug. Methods and Materials: Standard skin wounds were performed on 80 Wistar rats, distributed into four groups: no treatment (sham group), laser only (lambda 670 nm, 9mW, 0.031 W/cm(2), 4 J/cm(2), single dose after surgery), dexamethasone only (2 mg/kg 1 h before surgery), and laser with dexamethasone. Tissue was examined histologically to evaluate edema, presence of polymorphonuclear, mononuclear cells, and collagen. The analysis of myofibroblasts was assessed by immunohistochemistry and transmission electron microscopy. The intensity was rated semiquantitatively. Results: The results showed that laser and dexamethasone acted in a similar pattern to reduce acute inflammation. Collagen synthesis and myofibroblasts were more intense in the laser group (p=0.048), whereas animals treated with dexamethasone showed lower results for these variables. In a combination of therapies, the synthesis of collagen and actin and desmin-positive cells was less than laser group. Conclusions: Laser was effective in reducing swelling and polymorphonuclear cells and accelerated tissue repair, even in the presence of dexamethasone.