Ultrasound effect on level of stress proteins and arthritic histology in experimental arthritis

Objective: To investigate the effect of ultrasound on the levels of stress protein in experimental arthritis and their relation to the therapeutic eff ects on arthritic cartilage repair. Methods: Thirty-six rats with similar degree of early arthritis were divide d at random into two groups, In group s, 18 rats received sonication; in gr oup c, 18 control rats received sham sonication. The severity of induced ar thritis 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 pr oteins extracted from chondrocytes of arthritic cartilage, The severity ind ex, density of immunostained chondrocytes, and histopathologic changes at v arious periods were also studied in each group. Results: The density of stress protein was increased markedly in treated ra ts after sonication and it was closely related to the repair of arthritic c artilage. Once the pathohistology of arthritic cartilage improved, stress p rotein 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 we ll correlated with the therapeutic effect of ultrasound to preserve chondro cytes and bring about the repair of arthritic cartilage. (C) 1999 by the Am erican Congress of Rehabilitation Medicine and the American Academy of Phys ical Medicine and Rehabilitation.