Treatment with calcitonin suppresses the responses of bone, cartilage, andsynovium in the early stages of canine experimental osteoarthritis and significantly reduces the severity of the cartilage lesions

Objective, To relate the rate of bone resorption to serum levels of both hy aluronan (HA) and antigenic keratan sulfate (KS) in canine experimental ost eoarthritis (OA) and to evaluate the effects of calcitonin on these paramet ers and the OA lesions of the unstable knee, Methods, Twenty-two dogs underwent anterior cruciate ligament transection ( ACLT) and 6 dogs underwent sham operation. Urinary pyridinium crosslinks we re quantified by high-performance liquid chromatography. Immunoassays quant ified hyaluronan (HA) and antigenic KS. Macroscopic and histologic OA lesio ns were scored. Calcitonin treatment was started on day 14 postsurgery and stopped on either day 49 or day 104 postsurgery. Control dogs and all treat ed dogs were killed on day 105, Results. All ACLT joints developed OA. In contrast to sham-operated animals , all operated dogs exhibited an early and sustained rise in the levels of their urinary and serum markers. Calcitonin markedly reduced the levels of these markers and the severity of OA lesions. Furthermore, the longer the p eriod of calcitonin therapy, the lower the score of the OA lesions. Conclusion, Bone, synovium, and articular cartilage all appear to be involv ed in the state of hypermetabolism that develops in unstable joints. Furthe rmore, the rate of bone resorption increases markedly in the early stages o f this OA model and is likely to contribute to cartilage breakdown, Since c alcitonin reduced the severity of OA changes, this form of therapy may have benefits for humans who have recently experienced a traumatic knee injury.