The effects of joint immobilization on articular cartilage of the knee in previously exercised rats

• Published in: Journal of anatomy 2013-05, Vol.222 (5), p.518-525
• Main Authors: Maldonado, Diogo Correa, Silva, Marcelo Cavenaghi Pereira da, Neto, Semaan El‐Razi, Souza, Mônica Rodrigues, Souza, Romeu Rodrigues
• Format: Article
• Language: English
• Subjects: Animals; articular cartilage; Atrophy - prevention & control; Cartilage; Cartilage, Articular - pathology; Cartilage, Articular - physiology; Collagen - analysis; Exercise; immobilization; Immobilization - adverse effects; Joint Diseases - physiopathology; Joint Diseases - prevention & control; Knee; knee joint; Knee Joint - physiology; Male; Original; Physical Conditioning, Animal; Physical fitness; Rats; Rats, Wistar; Rodents
• ISSN: 0021-8782; 1469-7580
• DOI: 10.1111/joa.12036

Studies have determined the effects of joint immobilization on the articular cartilage of sedentary animals, but we are not aware of any studies reporting the effects of joint immobilization in previously trained animals. The objective of the present study was to determine whether exercise could prevent degeneration of the articular cartilage that accompanies joint immobilization. We used light microscopy to study the thickness, cell density, nuclear size, and collagen density of articular cartilage of the femoral condyle of Wistar rats subjected to aerobic physical activity on an adapted treadmill five times per week. Four groups of Wistar rats were used: a control group (C), an immobilized group (I), an exercised group (E), and an exercised and then immobilized group (EI). The right knee joints from rats in groups I and EI were immobilized at 90 °C of flexion using a plastic cast for 8 weeks. Cartilage thickness decreased significantly in group I (mean, 120.14 ± 15.6 μm, P