The role of mucopolysaccharide induction in treatment of experimental osteoarthritis in rats by ultrasound.

Therapeutic ultrasound has been used in the treatment of osteoarthritis for the relief of symptom and improvement of functional status. In recent study, we found that ultrasound enhances cartilage repair in experimental early stage osteoarthritis, and prevents deteriorative changes in later stages. In the present study, we further investigate the bioeffects of ultrasound on cartilage matrix of experimental arthritis. Fifty-four rats with three different degrees of papain induced osteoarthritis classified by 99m-Tc pertechnetate bone scan were collected for ultrasound treatment. The changes in their arthritic severity after sonication treatment and two months after treatment were measured using 99m-Tc bone scan. The histopathological changes were evaluated through light microscope after disarticulation sections (H.E. stain), and the changes in mucopolysaccharide density in cartilage matrix were measured using a Optimas scanner analyzer after Alcian blue staining. The results showed that the density of mucopolysaccharide rose in the initial stage of induced arthritis, and decreased progressively in the later stage. The density of mucopolysaccharide increased upon complete sonication more for the treated rats than for the controls, and this was closely related with the improvement in histopathological findings, but inversely with the changes in arthritic severity. In conclusion, therapeutic ultrasound enhances mucopolysaccharide synthesis of arthritic cartilage, and results in the repair of arthritic cartilage in the early stage of induced arthritis and the prevention of deteriorative changes in later stages.