Objective: To investigate the effect of ultrasound on the levels of stress protein in experimental arthritis and their relation to the therapeutic effects on arthritic cartilage repair.
Methods: Thirty-six rats with similar degree of early arthritis were divided at random into two groups. In group s, 18 rats received sonication; in group c, 18 control rats received sham sonication. The severity of induced arthritis was evaluated from bone scan with technetium-99m. The presence and changes of stress protein were identified from immunostain of SP72 antibody from frozen sections of arthritic cartilage and from electrophoresis of proteins extracted from chondrocytes of arthritic cartilage. The severity index, density of immunostained chondrocytes, and histopathologic changes at various periods were also studied in each group.
Results: The density of stress protein was increased markedly in treated rats after sonication and it was closely related to the repair of arthritic cartilage. Once the pathohistology of arthritic cartilage improved, stress protein declined significantly in the follow-up period.
Conclusion: Therapeutic ultrasound can enhance stress protein production in arthritic chondrocytes. The extragenic production of stress protein was well correlated with the therapeutic effect of ultrasound to preserve chondrocytes and bring about the repair of arthritic cartilage.