title: Light-emitting diode therapy reduces persistent inflammatory pain: Role of interleukin 10 and antioxidant enzymes.
abstract: BACKGROUND
  During the last decades, the use of light-emitting diode therapy (LEDT) has increased significantly for the treatment of wound healing, analgesia and inflammatory processes. Nevertheless, scientific data on the mechanisms responsible for the therapeutic effect of LEDT are still insufficient. Thus, this study investigated the analgesic, anti-inflammatory and anti-oxidative effect of LEDT in the model of chronic inflammatory hyperalgesia.
  
  
  METHODS
  Mice injected with Complete Freund's Adjuvant (CFA) underwent behavioral, i.e. mechanical and hot hyperalgesia; determination of cytokine levels (tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), IL-10), oxidative stress markers (protein carbonyls and thiobarbituric acid reactive species (TBARS)) and antioxidant enzymes (catalase (CAT) and superoxide dismutase (SOD)). Additionally, mice were pretreated with either naloxone or fucoidin and mechanical hyperalgesia was assessed.
  
  
  RESULTS
  LEDT inhibited mechanical and thermal hyperalgesia induced by CFA injection. LEDT did not reduce paw edema, neither influenced the levels of TNF-α and IL1-β; although it increased the levels of IL-10. LEDT significantly prevented TBARS increase in both acute and chronic phases post-CFA injection; whereas protein carbonyl levels were reduced only in the acute phase. LEDT induced an increase in both SOD and CAT activity, with effects observable in the acute but not in the chronic. And finally, pre-administration of naloxone or fucoidin prevented LEDT analgesic effect.
  
  
  CONCLUSIONS
  These data contribute to the understanding of the neurobiological mechanisms involved in the therapeutic effect of LEDT as well as provides additional support for its use in the treatment of painful conditions of inflammatory etiology.
authors.affiliation: Experimental Neuroscience Laboratory (LaNEx), University of Southern Santa Catarina at Palhoça, Santa Catarina, Brazil; Postgraduate Program in Health Sciences, University of Southern Santa Catarina, Santa Catarina, Brazil. Electronic address: danielmartinsfisio@hotmail.com.
authors.forename: D F
authors.initials: DF
authors.lastname: Martins
authors.affiliation: Experimental Neuroscience Laboratory (LaNEx), University of Southern Santa Catarina at Palhoça, Santa Catarina, Brazil; Graduate Program in Neuroscience, Center of Biological Sciences, Federal University of Santa Catarina, Trindade, Florianópolis, Santa Catarina, Brazil.
authors.forename: B L
authors.initials: BL
authors.lastname: Turnes
authors.affiliation: Experimental Neuroscience Laboratory (LaNEx), University of Southern Santa Catarina at Palhoça, Santa Catarina, Brazil.
authors.forename: F J
authors.initials: FJ
authors.lastname: Cidral-Filho
authors.affiliation: Laboratory of Neurobiology of Pain and Inflammation, Department of Physiological Sciences, Centre of Biological Sciences, University Federal of Santa Catarina, Florianópolis, Santa Catarina, Brazil.
authors.forename: F
authors.initials: F
authors.lastname: Bobinski
authors.affiliation: Experimental Neuroscience Laboratory (LaNEx), University of Southern Santa Catarina at Palhoça, Santa Catarina, Brazil; Postgraduate Program in Health Sciences, University of Southern Santa Catarina, Santa Catarina, Brazil.
authors.forename: R F
authors.initials: RF
authors.lastname: Rosas
authors.affiliation: Postgraduate Program in Health Sciences, University of Southern Santa Catarina, Santa Catarina, Brazil; Laboratory of Clinical and Experimental Pathophysiology, University of Southern Santa Catarina at Tubarão, Santa Catarina, Brazil.
authors.forename: L G
authors.initials: LG
authors.lastname: Danielski
authors.affiliation: Postgraduate Program in Health Sciences, University of Southern Santa Catarina, Santa Catarina, Brazil; Laboratory of Clinical and Experimental Pathophysiology, University of Southern Santa Catarina at Tubarão, Santa Catarina, Brazil.
authors.forename: F
authors.initials: F
authors.lastname: Petronilho
authors.affiliation: Laboratory of Neurobiology of Pain and Inflammation, Department of Physiological Sciences, Centre of Biological Sciences, University Federal of Santa Catarina, Florianópolis, Santa Catarina, Brazil.
authors.forename: A R S
authors.initials: AR
authors.lastname: Santos
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D004195:Disease Models, Animal; D005620:Freund's Adjuvant; D006358:Hot Temperature; D006930:Hyperalgesia / Q000378:metabolism / Q000628:therapy*; D007249:Inflammation / Q000378:metabolism / Q000628:therapy; D016753:Interleukin-10 / Q000378:metabolism*; D053583:Interleukin-1beta / Q000378:metabolism; D008297:Male; D051379:Mice; D018384:Oxidative Stress / Q000502:physiology; D010146:Pain / Q000378:metabolism; D059408:Pain Management / Q000295:instrumentation / Q000379:methods*; D010789:Phototherapy / Q000295:instrumentation / Q000379:methods*; D013482:Superoxide Dismutase / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D014110:Touch; D016896:Treatment Outcome; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D000975:Antioxidants; C556062:IL10 protein, mouse; C587672:IL1B protein, mouse; D053583:Interleukin-1beta; D017392:Thiobarbituric Acid Reactive Substances; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D005620:Freund's Adjuvant; D002374:Catalase; D013482:Superoxide Dismutase
keywords: inflammation; low-level light therapy; mice; persistent pain