Effect of calcitonin on experimentally induced osteoarthritis in adult male rabbits: biochemical, histomorphometric, and immunohistochemical study

ABSTRACT

Osteoarthritis [OA] is the most common joint disease. This disease progresses slowly and develops over years. Conservative treatment regimens for OA treat the symptoms but not the disease. The purpose of this study was to investigate the role of salmon calcitonin in the changes that occur in the articular cartilage and subchondral bone following experimentally induced OA in rabbits. Thirty adult male New Zealand white rabbits were used. They were divided into three groups control; osteoarthitic; and calcitonin-prophylactic. On sacrifice, blood samples were withdrawn to estimate serum alkaline phosphatase, calcium, and phosphorus levels. Articular cartilage and subchondral bone were processed for histological, immunohistochemical, and morphometric studies. Estimation of bone calcium and phosphorous concentrations was also carried out. Articular cartilage of osteoarthritic rabbits showed a disrupted articular surface with a reduction of the subchondral bone thickness. An irregular or a doubled tide-mark was also seen. There was a change in the normal distribution of the chondrocytes with loss of the superficial layer. Weak Periodic Acid Schiff's and Alcian blue staining with a negative BCL-2 reaction were also present in the articular cartilage. Bone calcium and phosphorus concentrations were significantly decreased in OA compared with those of the control group. Serum alkaline phosphatase level was significantly increased in the OA group compared with the control group. In the calcitonin-prophylactic group, there was an improvement in biochemical, histological, and immunohistochemical changes. Calcitonin had a protective effect on the OA changes induced in the articular cartilage of rabbits. Also, it played a role in improving bone calcium and phosphorus content and integrity of the bone matrix