THE EFFECT OF ULTRASONICALLY INDUCED CAVITATION ON THE HYALURONAN POLYMER

Hyaluronan solutions were subjected to damage from ultrasonically gene rated cavitation. The shearing effect of the cavitation on the hyaluro nan was monitored by viscometry and polymer molecular weight analysis. Cavitation caused a decrease in fluid viscosity coupled with an incre ase in Newtonian flow behaviour in all hyaluronan solutions studied, a mechanical characteristic known to occur in pathological synovial flu ids. Polymer molecular weight was shown to be markedly decreased over the period of cavitation demonstrating cleavage of the hyaluronan poly mer had occurred. Thus cavitation activity leads to cleavage of the hy aluronan polymer which manifests itself as a deterioration in the flui d mechanical properties. Previous work revealed that ultrasonic cavita tion in vitro caused similar articular cartilage damage to human osteo arthrotic articular cartilage in vivo. It is our postulate that cavita tion induced degradation of synovial fluid hyaluronan and its mechanic al properties would lead to increased damage to the articular cartilag e and ultimately loss of joint function. Therefore cavitation activity could be involved as a possible aetiological factor in arthritic dise ase.