Using Rheology to Probe the Mechanism of Joint Lubrication: Polyelectrolyte/protein interactions in Synovial Fluid

Abstract

ABSTRACTThe outstanding lubricating properties of synovial fluid, found in freely moving mammalian joints, may be due to intermolecular associations between hyaluronic acid, an anionic polysaccharide, and the plasma proteins. A synovial fluid model comprised of hyaluronic acid and the plasma proteins albumin and γ-globulins, was constructed. Rheological measurements reveal a pronounced viscoelasticity with a strong shear history dependence for the synovial fluid model and the plasma protein solutions at low shear rates. The addition of the anti-inflammatory drug D-Penicillamine to the solution alters the rheology of the synovial fluid model. We present two ideas about the structural features of synovial fluid that may explain this viscoelasticity and suggest further experimental techniques that can be used to test these ideas.