Hyaluronan in the synovial fluid

Hyaluronan is an essential component of the synovial fluid. It is a biopolymer made of repeating disaccharide units, which gives the synovial fluid its characteristic viscoelastic properties. It enables the fluid to act as a lubricant, a shock absorber and a filter controlling the movement of cells and large molecules within the joint.2,3

Under gradual shear stress, sodium hyaluronate acts as a lubricant

Under sudden loading sodium hyaluronate acts as a shock absorber

Sodium hyaluronate acts as a filter, hindering the movement of potentially damaging cells and molecules

Hyaluronan in the cartilage and synovial membrane

Hyaluronan forms a coating over the surface of the articular cartilage and the synovial membrane.4 This coating acts as a viscoelastic shield, protecting the joint structures from mechanical damage. Hyaluronan also protects from pain by masking the local nociceptors.5,6 In addition, the coating hinders the migration of free radicals and other inflammatory cells into the joint space.7-9

Hyaluronan also forms the backbone of the proteoglycan aggregates that are essential for the structural and functional integrity of the articular cartilage.10,11