REDUCTION OF INTERLEUKIN-1.BETA. EXPRESSION IN RHEUMATOID ARTHRITIS BY LINEAR POLARIZED NEAR INFRARED LIGHT IRRADIATION

Abstract

Background: Rheumatoid arthritis (RA) is a systemic autoimmune disorder that involves inflammation and pain of joints. Low-level light therapy (LLLT) is being evaluated for treating RA. However, the molecular basis mechanism underlying the effectiveness of linear polarized near infrared light irradiation (LPIL) is unclear. It has been reported that interleukin 1β (IL-1β) plays a key role in the progression of RA.Aim: The objective of this study was to determine whether LPIL (Super Lizer™; SL) decrease gene expression and production IL-1β in human RA synovial cells, MH7A, and RA joint tissue of collagen-induced-rheumatoid arthritis (CIA) rats.Materials and Methods: IL-1β challenged MH7A and CIA rat joints were irradiated with SL. Total RNA was isolated from MH7A, and gene expression profiles were analyzed using DNA microarray.The mRNA levels were confirmed by reverse transcription-polymerase chain reaction (RT-PCR) and real-time PCR. The production of IL-1β in rat knee joints was analyzed by immunohistochemistry.Results: DNA microarray analysis showed that IL-1β increased IL-1β gene expression in MH7A, and SL significantly reduced its IL-1β mRNA level. The reduction of IL-1β mRNA level by SL was successfully confirmed by reverse RT-PCR and real-time PCR. SL reduced the swelling of CIA rat knee joints, and the immunohistochemical study demonstrated that a strong IL-1β staining in synovial membrane tissue of CIA rat joint, and the immuno-staining was significantly reduced by SL.Conclusion: Since autocrine IL-1β production has been identified to be an important proinflammatory cytokine in the pathogenesis of RA, the reduction of IL-1β expression in RA synovial cells is one of mechanisms in reduction of the inflammation in RA by SL.