title: Reduction of interleukin-6 expression in human synoviocytes and rheumatoid arthritis rat joints by linear polarized near infrared light (Superlizer) irradiation.
abstract: BACKGROUND
  Rheumatoid arthritis (RA) is a systemic autoimmune disorder that involves inflammation and pain of joints. Low-level laser irradiation is being evaluated for treating RA, however, the effectiveness of linear polarized near infrared light (SuperLizer; SL) irradiation is unclear.
  
  
  OBJECTIVE
  It has been reported that interleukin 6 (IL-6) plays a key role in the progression of RA. In our previous study, using DNA microarray analysis, we examined the gene expression profiling of human rheumatoid fibroblast-like synoviocyte MH7A in response to IL-1ß administration and SL irradiation. As a result, IL-6 was listed in altered gene as increased by IL-1ß and decreased by SL irradiation.
  
  
  METHODS
  The reduction of IL-6 gene expression in MH7A by SL irradiation was confirmed by reverse transcription polymerase chain reaction (RT-PCR) and real-time PCR. Effect of SL irradiation on the RA inflammation in the collagen induced arthritis (CIA) rats was also studied by measuring temperature. IL-6 production in knee joint of rats was analyzed by immunohisto-chemistry.
  
  
  RESULTS
  Scatter plot analysis demonstrated that an increase in IL-6 gene expression by IL-1ß was reduced by SL irradiation. The reduction of IL-6 mRNA level by SL irradiation was successfully confirmed by RT-PCR and real-time PCR. SL irradiation treated CIA rat decreased the temperature of knee joints. The immunohistochemical analysis demonstrated a strong IL-6 staining in synovial membrane tissue of CIA rat joint, and SL irradiation significantly reduced the staining.
  
  
  CONCLUSIONS
  Since IL-6 has been identified to be an important proinflarnmatory cytokine in the pathogenesis of RA, the reduction of IL-6 expression is one of mechanisms in reduction of inflammation in RA joints by SL irradiation suggesting that SL irradiation may be useful for RA therapy.
  
  
  CONCLUSIONS
  SL irradiation reduced IL-6 gene expression in MH7A, and reduced inflammation and IL-6 protein expression in knee joint of CIA rats.
authors.affiliation: Departments of Biochemistry and Molecular Biology, Nihon University School of Dentistry at Matsudo.
authors.forename: Hidefumi
authors.initials: H
authors.lastname: Araki
authors.forename: Asayo
authors.initials: A
authors.lastname: Imaoka
authors.forename: Noboru
authors.initials: N
authors.lastname: Kuboyama
authors.forename: Yoshimitsu
authors.initials: Y
authors.lastname: Abiko
keywords: IL-6 expression; rat joint; rheumatoid arthritis; synovial cells