The effect of hyaluronan on CD44-mediated survival of normal and hydroxyl radical-damaged chondrocytes

Osteoarthritis Cartilage. 2003 Mar;11(3):208-16. doi: 10.1016/s1063-4584(02)00352-7.


Objective: To identify the CD44-receptor-mediated effects of 5-7 x 10(5)MW hyaluronan (HA, Hyalgan) on cell viability in normal and damaged human chondrocyte primary cultures isolated from articular cartilage.

Design: Primary cultures of human chondrocytes were established from normal articular biopsies and expanded to the second culture passage. The dose-response effects of HA on the viability of normal cultures were identified. Chondrocytes were then treated with either hypoxanthine (2 mM) and xanthine oxidase (20-60 mU), or with activated polymorphonuclear leukocytes (PMNs) to induce injury. Damaged and control cells were then treated with 5-7 x 10(5)HA in the previously identified optimal dose of 0.05 mg/ml. Viability was assessed at specific time periods for the chemically and PMN-damaged cells. To identify if HA effects were mediated by the CD44 receptor, chondrocytes were incubated with anti-CD44 antibody at saturating concentrations (5 microg/ml for 100,000 cells) to produce a maximum inhibition of HA binding. Cells were evaluated using the MTT viability assay, histology, electron microscopy and immunohistochemistry.

Results: Direct addition of HA (optimal dose, 0.5 mg/ml) significantly increased cell survival in normal chondrocyte primary cultures (P<0.05). Similarly, addition of this same dose of HA to cultures of free radical-damaged chondrocytes, restored the viability to baseline conditions. Cell viability rates dropped significantly (P<0.05) when CD44 receptor binding was inhibited, indicating that cell growth was mediated by the CD44 receptor.

Conclusions: HA (0.5 mg/ml of 5-7 x 10(5)) significantly increased the viability of normal human chondrocytes in primary culture and restored cell viability to near normal levels after oxidative cell injury.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cartilage, Articular / metabolism
  • Cell Survival / drug effects
  • Cells, Cultured
  • Chondrocytes / drug effects*
  • Dose-Response Relationship, Drug
  • Humans
  • Hyaluronan Receptors / metabolism*
  • Hyaluronic Acid / pharmacology*
  • Hypoxanthine / pharmacology
  • Immunohistochemistry / methods
  • Microscopy, Electron
  • Neutrophils / physiology
  • Xanthine Oxidase / pharmacology


  • Hyaluronan Receptors
  • Hypoxanthine
  • Hyaluronic Acid
  • Xanthine Oxidase