Effect of Low-Level Laser Therapy (LLLT) on Acute Neural Recovery and Inflammation-Related Gene Expression After Crush Injury in Rat Sciatic Nerve

Background and Objectives Peripheral nerve function can be debilitated by different kinds of injury. Low‐level laser therapy (LLLT) has been used successfully during rehabilitation to stimulate recovery. The aim of this study was to evaluate the effects of LLLT (660 nm, 60 J/cm2, 40 mW/cm2) on acute sciatic nerve injury. Materials and Methods Thirty Wistar male rats were divided into three groups: (1) Normal, intact nerves; (2) I3d, crushed nerves evaluated on Day‐3 post‐injury; (3) I + L3d, crushed nerves submitted to two sessions of LLLT and investigated at 3 days post‐injury. Sciatic nerves were removed and processed for gene expression analysis (real‐time PCR) of the pro‐inflammatory factors TWEAK, Fn14 and TNF‐α and extracellular matrix remodeling and axonal growth markers, such as TIMP‐1, MMP‐2, and MMP‐9. Zymography was used to determine levels of MMP‐2 and MMP‐9 activity and Western blotting was used to evaluate TNF‐α protein content. Shapiro–Wilk and Levene's tests were applied to evaluate data normality and homogeneity, respectively. One‐way ANOVA followed by Tukey test was used for statistical analysis with a significance level set at 5%. Results An increase in TNF‐α protein level was found in I + L3 compared to Normal and I3d (P