The effect of molecular weight on hyaluronan's cartilage boundary lubricating ability - alone and in combination with proteoglycan 4

J. J. Kwiecinski, S. G. Dorosz, T. E. Ludwig, S. Abubacker, M. K. Cowman, T. A. Schmidt

Research output: Contribution to journalArticle


Objectives: (1) assess the molecular weight dependence of hyaluronan's (HA) cartilage boundary lubricating ability, alone and in combination with proteoglycan 4 (PRG4), at physiological concentrations; (2) determine if HA and PRG4 interact in solution via electrophoretic mobility shift assay (EMSA). Methods: The cartilage boundary lubricating ability of a broad range of MW HA (20kDa, 132kDa, 780kDa, 1.5MDa, and 5MDa) at 3.33mg/ml, both alone and in combination with PRG4 at 450μg/ml, was assessed using a previously described cartilage-on-cartilage friction test. Static, μ static, Neq, and kinetic, <μ kinetic, Neq>, were calculated. An EMSA was conducted with PRG4 and monodisperse 150kDa and 1,000kDa HA. Results: Friction coefficients were reduced by HA, in a MW-dependent manner. Values of <μ kinetic, Neq> in 20kDa HA, 0.098 (0.089, 0.108), were significantly greater compared to both 780kDa, 0.080 (0.072, 0.088), and 5MDa, 0.079 (0.070, 0.089). Linear regression showed a significant correlation between both μ static, Neq and <μ kinetic, Neq>, and log HA MW. Friction coefficients were also reduced by PRG4, and with subsequent addition of HA; however the synergistic effect was not dependent on HA MW. Values of <μ kinetic, Neq> in PRG4, 0.080 (0.047, 0.113), were significantly greater than values of PRG4+various MW HA (similar in value, averaging 0.040 (0.033, 0.047)). EMSA indicated that migration of 150kDa and 1,000kDa HA was retarded when combined with PRG4 at high PRG4:HA ratios. Conclusions: These results suggest alterations in HA MW could significantly affect synovial fluid's cartilage boundary lubricating ability, yet this diminishment in function could be circumvented by physiological levels of PRG4 forming a complex, potentially in solution, with HA.

Original languageEnglish (US)
Pages (from-to)1356-1362
Number of pages7
JournalOsteoarthritis and Cartilage
Issue number11
StatePublished - Nov 1 2011



  • Cartilage boundary lubrication
  • Hyaluronan
  • Proteoglycan 4 (PRG4)

ASJC Scopus subject areas

  • Rheumatology
  • Biomedical Engineering
  • Orthopedics and Sports Medicine

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