High molecular weight hyaluronic acid down-regulates the gene expression of osteoarthritis-associated cytokines and enzymes in fibroblast-like synoviocytes from patients with early osteoarthritis

Osteoarthritis Cartilage. 2006 Dec;14(12):1237-47. doi: 10.1016/j.joca.2006.05.009. Epub 2006 Jun 30.


Objective: Activated synoviocytes play important roles in the progression of human osteoarthritis (OA). Intra-articular injection of high molecular weight hyaluronic acid (HMW-HA) has been used as viscosupplementation for knee OA but its effect on synoviocytes remains undisclosed. This study aims to investigate the effects of HMW-HA on the gene expression of 16 OA-associated cytokines and enzymes, including interleukin (IL)-1beta, IL-6, IL-8, leukemia inhibitory factor (LIF), tumor necrosis factor (TNF)-alpha, TNF-alpha converting enzyme (TACE), matrix metalloproteinase (MMP)-1, MMP-2, MMP-3, MMP-9, MMP-13, tissue inhibitor of metalloproteinase (TIMP)-1, TIMP-2, aggrecanase-1, aggrecanase-2, and inducible nitric oxide synthase (iNOS), in fibroblast-like synoviocytes (FLS) from patients with early stage OA.

Method: Synovial fluid-derived FLS were obtained from the knees of 15 patients with early stage OA. IL-1-stimulated or unstimulated FLS were cultured with or without the treatment of 600-800kDa HMW-HA. Moreover, blocking experiments with anti-CD44 monoclonal antibodies (mAb) were used to examine the involvement of CD44 in HMW-HA effects. We designed and validated the real-time quantitative polymerase chain reaction (Q-PCR) assays with SYBR Green dyes for simultaneous quantification of the expression of the 16 genes.

Results: HMW-HA down-regulated IL-8 and iNOS gene expression in unstimulated FLS and down-regulated aggrecanase-2 and TNF-alpha gene expression in IL-1-stimulated FLS. CD44 blocking inhibited the down-regulatory effects of HMW-HA on gene expression.

Conclusion: HMW-HA may have a structure-modifying effect for OA by down-regulation of aggrecanase-2 in FLS. HMW-HA also has an anti-inflammatory effect by down-regulation of TNF-alpha, IL-8, and iNOS in FLS. These effects may be mediated through the interaction of CD44 and HMW-HA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ADAM Proteins / biosynthesis
  • ADAM Proteins / genetics
  • ADAMTS5 Protein
  • Cytokines / biosynthesis*
  • Cytokines / genetics
  • Dose-Response Relationship, Drug
  • Down-Regulation / drug effects*
  • Fibroblasts / immunology
  • Fibroblasts / metabolism
  • Humans
  • Hyaluronan Receptors / immunology
  • Hyaluronic Acid / pharmacology*
  • Interleukin-1 / immunology
  • Interleukin-8 / biosynthesis
  • Interleukin-8 / genetics
  • Molecular Weight
  • Nitric Oxide Synthase Type II / biosynthesis
  • Nitric Oxide Synthase Type II / genetics
  • Osteoarthritis, Knee / immunology
  • Osteoarthritis, Knee / metabolism*
  • Polymerase Chain Reaction / methods
  • Synovial Fluid / immunology
  • Synovial Fluid / metabolism*
  • Tumor Necrosis Factor-alpha / biosynthesis
  • Tumor Necrosis Factor-alpha / genetics


  • CD44 protein, human
  • Cytokines
  • Hyaluronan Receptors
  • Interleukin-1
  • Interleukin-8
  • Tumor Necrosis Factor-alpha
  • Hyaluronic Acid
  • Nitric Oxide Synthase Type II
  • ADAM Proteins
  • ADAMTS5 Protein
  • ADAMTS5 protein, human