Effects of low-level laser therapy on joint pain, synovitis, anabolic, and catabolic factors in a progressive osteoarthritis rabbit model

Lasers Med Sci. 2014 Nov;29(6):1875-85. doi: 10.1007/s10103-014-1600-x. Epub 2014 Jun 3.

Abstract

The aim of this study was to investigate the effect of low-level laser therapy (LLLT) on short-term and long-term joint pain, synovitis, anabolic, and catabolic factors in the cartilage of a rabbit model with progressive osteoarthritis (OA) induced by anterior cruciate ligament transection (ACLT). A total of 160 New Zealand white rabbits were randomly assigned into two groups (ACLT group and LLLT group). All rabbits received ACLT surgery, and 2-, 4-, 6-, and 8-week treatment after the surgery, with 20 rabbits being tested biweekly over every study period. The LLLT group received LLLT with a helium-neon (He-Ne) laser (830 nm) of 1.5 J/cm(2) three times per week, and the ACLT group received placebo LLLT with the equipment switched off. Long-term and short-term pain was tested via weight-bearing asymmetry; synovitis was assessed histologically; and knee joint cartilage was evaluated by gross morphology, histology, and gene expression analysis of anabolic and catabolic factors. The histological assessment of pain and synovitis showed that at least 6-week intermittent irradiation of LLLT could relief knee pain and control synovium inflammation. Gross morphologic inspection and histological evaluation showed that 6 weeks of LLLT could decrease cartilage damage of medical femoral condyle and 8 weeks of LLLT could decrease cartilage damage of medical and lateral femoral condyles and medical tibial plateau. Gene expression analysis revealed two results: At least 6 weeks of LLLT could decrease production of catabolic factors, for example, interleukin 1β (IL-1β), inducible nitric oxide synthase (iNOS), and MMP-3, and slow down the loss of anabolic factors, mainly TIMP-1. Eight weeks of LLLT treatment could slow down the loss of collagen II, aggrecan, and anabolic factors, mainly transforming growth factor beta (TGF-β). The study suggests that LLLT plays a protective role against cartilage degradation and synovitis in rabbits with progressive OA by virtue of the regulation of catabolic and anabolic factors in the cartilage.

MeSH terms

  • Animals
  • Anterior Cruciate Ligament / metabolism
  • Arthralgia / radiotherapy*
  • Cartilage / radiation effects
  • Cartilage, Articular / radiation effects*
  • Chondrocytes / radiation effects
  • Disease Models, Animal
  • Disease Progression
  • Femur / pathology
  • Femur / radiation effects
  • Gene Expression Profiling
  • Gene Expression Regulation
  • Knee Joint / metabolism
  • Knee Joint / radiation effects
  • Low-Level Light Therapy / methods*
  • Osteoarthritis / radiotherapy*
  • Pain Management
  • Rabbits
  • Synovitis / radiotherapy*
  • Tibia / radiation effects
  • Weight-Bearing