ヒアルロン酸の分子量変化が軟骨表層へのタンパク質吸着および潤滑機能に及ぼす影響の評価

抄録

Various molecules existing in synovial fluid contribute to lubrication of living articular cartilage. However, the tribological molecular mechanism at the frictional interface of cartilage tissue has not been elucidated. It has been reported that the molecular weight of hyaluronic acid (HA) in synovial fluid decrease in patients with joint diseases, and this change in the HA molecular weight would have an influence on the adsorption of proteins in synovial fluid on the friction surface of cartilage tissue. In this study, we directly observed the protein adsorption and the morphological change of collagen fiber at the surface layer of cartilage tissue before and after friction by using a multiphoton excitation microscope. Furthermore, we examined an effect of the difference in HA molecular weight on the frictional properties and the adsorbed film on cartilage tissue. In the results of friction measurement using high molecular weight HA, the friction coefficient decreased significantly compared to those using low molecular weight HA or PBS. In addition, different protein adsorption behavior, especially in γ-globulin, to the cartilage surface was observed depending on HA molecular weight, and it was suggested that a thickened layer of γ-globulin with high molecular weight HA played an important role of the low frictional property in cartilage tissue.