Dr. Sah has received consulting fees, speaking fees, and/or honoraria from BioMimetic Therapeutics and Carbylan BioSurgery (less than $10,000 each).
Effects of equine joint injury on boundary lubrication of articular cartilage by synovial fluid: Role of hyaluronan
Article first published online: 27 AUG 2012
Copyright © 2012 by the American College of Rheumatology
Arthritis & Rheumatism
Volume 64, Issue 9, pages 2917–2926, September 2012
How to Cite
Antonacci, J. M., Schmidt, T. A., Serventi, L. A., Cai, M. Z., Shu, Y. L., Schumacher, B. L., McIlwraith, C. W. and Sah, R. L. (2012), Effects of equine joint injury on boundary lubrication of articular cartilage by synovial fluid: Role of hyaluronan. Arthritis & Rheumatism, 64: 2917–2926. doi: 10.1002/art.34520
- Issue published online: 27 AUG 2012
- Article first published online: 27 AUG 2012
- Accepted manuscript online: 17 MAY 2012 02:29PM EST
- Manuscript Accepted: 19 APR 2012
- Manuscript Received: 17 FEB 2011
- National Science Foundation
- Howard Hughes Medical Institute (through a Professors Program award to the University of California at San Diego in support of Dr. Sah)
- National Science Foundation Graduate Research Fellowship
- University of California at San Diego Chancellor's Research Scholarship
To compare equine synovial fluid (SF) from injured and control joints for cartilage boundary lubrication function; concentrations of the putative boundary lubricant molecules hyaluronan (HA), proteoglycan 4 (PRG4), and surface-active phospholipids (SAPLs); relationships between lubrication function and composition; and lubrication restoration by addition of HA.
Equine SF from normal joints, joints with acute injury, and joints with chronic injury were analyzed for boundary lubrication of normal articular cartilage (kinetic friction coefficient [μkinetic]). Equine SF samples were analyzed for HA, PRG4, and SAPL concentrations and HA molecular weight distribution. The effect of the addition of HA, of different concentrations and molecular weight, on the μkinetic of equine SF samples from normal joints and joints with acute injury was determined.
The μkinetic of equine SF from joints with acute injury (0.036) was higher (+39%) than that of equine SF from normal joints (0.026). Compared to normal equine SF, SF from joints with acute injury had a lower HA concentration (−30%) of lower molecular weight forms, higher PRG4 concentration (+83%), and higher SAPL concentration (+144%). Equine SF from joints with chronic injury had μkinetic, PRG4, and SAPL characteristics intermediate to those of equine SF from joints with acute injury and normal equine SF. Regression analysis revealed that the μkinetic value decreased with increasing HA concentration in equine SF. The friction-reducing properties of HA alone improved with increasing concentration and molecular weight. The addition of high molecular weight HA (4,000 kd) to equine SF from joints with acute injury reduced the μkinetic to a value near that of normal equine SF.
In the acute postinjury stage, equine SF exhibits poor boundary lubrication properties, as indicated by a high μkinetic. HA of diminished concentration and molecular weight may be the basis for this, and adding HA to deficient equine SF restored lubrication function.