title: Effect of low-level laser therapy (LLLT) on acute neural recovery and inflammation-related gene expression after crush injury in rat sciatic nerve.
abstract: OBJECTIVE
  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/cm(2) , 40 mW/cm(2) ) on acute sciatic nerve injury.
  
  
  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 < 0.05). Zymography showed an increase in proMMP-9 activity, in both I3d and I + L3d groups (P < 0.05). The increase was more evident in I + L3d (P = 0.02 compared to I3d). Active-MMP-9 isoform activity was increased in I + L3d compared to Normal and I3d groups (P < 0.05). Furthermore, the activity of active-MMP-2 isoform was increased in I3d and I + L3 (P < 0.05). An increase in TIMP-1 expression was observed in both I3d and I + L3d groups (P < 0.05).
  
  
  CONCLUSIONS
  The current study showed that LLLT increased MMPs activity, mainly MMP-9, and TNF-α protein level during the acute phase of nerve injury, modulating inflammation. Based on these results, it is recommended that LLLT should be started as soon as possible after peripheral nerve injury.
authors.affiliation: Laboratory of Neurological Physiotherapy Research, Physical Therapy, Department, Federal University of São Carlos (UFSCar), São Carlos, 13565-905, SP, Brazil.
authors.forename: Carolina C
authors.initials: CC
authors.lastname: Alcântara
authors.forename: Davilene
authors.initials: D
authors.lastname: Gigo-Benato
authors.forename: Tania F
authors.initials: TF
authors.lastname: Salvini
authors.forename: Alexandre L R
authors.initials: AL
authors.lastname: Oliveira
authors.forename: Juanita J
authors.initials: JJ
authors.lastname: Anders
authors.forename: Thiago L
authors.initials: TL
authors.lastname: Russo
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D015153:Blotting, Western; D005786:Gene Expression Regulation / Q000528:radiation effects; D007249:Inflammation / Q000209:etiology / Q000235:genetics / Q000378:metabolism; D054023:Lasers, Semiconductor / Q000627:therapeutic use*; D028022:Low-Level Light Therapy; D008297:Male; D059348:Peripheral Nerve Injuries / Q000150:complications / Q000235:genetics / Q000378:metabolism / Q000532:radiotherapy*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D020127:Recovery of Function / Q000528:radiation effects; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012584:Sciatic Nerve / Q000293:injuries* / Q000378:metabolism; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers