抄録
It has been reported that intraarticular injection of Hyaluronate (HA), especially that of high molecular weight (MW), provides symptomatic relief and improves joint function in arthritic joints. However, neither the mode of action nor mechanism of the therapeutic effect is fully understood.
We subsequently tried to clarify the effect of HA injection from the aspect of joint lubrication. First, using an apparatus with which it was possible to measure the thickness and the pressure of the fluid film formed between articular cartilage and a glass plate under a loading condition, we investigated the results with high MWHA in saline in comparison with those of low MWHA in saline. A thicker fluid film with higher pressure was maintained by introducing high MWHA. This suggests that better fluid film lubrication becomes possible by injection of high MWHA in saline into a joint, thus preventing the involved surfaces from direct contact and protecting them.
Second, we measured the coefficient of friction (CF) between articular cartilage and a glass plate using a pin-on-disc device and investigated the change of CF by adding HA of high MW or low MW in saline. The results showed that CF always decreased when introducing HA in saline. The percentage of decrease was about 60% with high MWHA, while 35% with low MWHA, suggesting that high MWHA improves joint lubrication by forming a lubricating film on the joint surface. It therefore seems that high MWHA improves joint lubrication through preventing the involved joint surface from experiencing friction and thus protects the surface.
