Gross and histomorphological effects of therapeutic ultrasound (1 Watt/Cm 2) in exprerimental acute traumatic arthritis in donkeys

Abstract

Summary Acute aseptic arthritis was induced in 8 healthy donkeys aged 3–4 years and weighing 80–100 kg. The animals were divided into two groups (A and B) of four animals each. Group A served as a control where as in group B pulsed ultrasound therapy was applied for 10 minutes @ 1 Watt/Cm 2 from day 2 to 8 after induction of arthritis. The gross changes in the joint capsule, synovial membrane and articular cartilage were quite mild in ultrasound treated animals as compared to controls. Microscopically, the joint capsule showed complete sloughing of the intimal layer and the subintimal layer showed severe inflammatory reaction or even complete necrosis of the fibrous capsule and synovial membrane in untreated animals. The joint capsule of ultrasound treated animals showed an advanced healing stage of the synovial membrane though still some inflammatory reaction was present in the subintimal layer. Synovial membrane of untreated animals showed less of acid mucopolysaccharides material and more of neutral mucopolysaccharides as compared to treated animals. Calcium deposition was not detectable in the joint capsule of the treatment group. Degeneration of articular cartilage was observed microscopically in control animals as marked by fibrillation and desquamation of perichondrial tissue with necrosis of chondrocytes in different layers or even complete sloughing of the articular cartilage. Articular cartilage of ultrasound treated animals had mild changes in the superficial layer (devoid of chondrocytes) and the rest of the cartilage layers were histologically normal.