Biochemical changes in articular cartilage after joint immobilization by casting or external fixation

摘要: Knees of mature dogs were immobilized for 6 weeks by long-leg casts allowing 8 degrees-15 degrees motion, a model studied others, or with external fixators, new, more severe that kept the joints rigid. Some animals allowed to recover 1 week after immobilization period. Articular cartilage was examined histologically and biochemically. After immobilization, water increased 7% in both casted fixator-immobilized compared normal knee cartilage, while hexuronic acid 23 28% lower, respectively. The limited motion permitted resulted smaller depression proteoglycan synthesis less loss during than occurred rigid fixator group. protective effect shown clearly recovery period: as measured content, from had almost recovered within week, whereas group experienced little no treatment. In contrast previous studies others joints, newly synthesized [35S]sulfate-labeled accumulated unlabeled proteoglycans cartilages able form complexes exogenous hyaluronic same extent those control cartilage. Thus, failure bind hyaluronate is not mechanism accelerated loss. turnover appears be caused combination decreased proteolysis secreted proteoglycans.(ABSTRACT TRUNCATED AT 250 WORDS)