Effect of antigen-induced synovitis on the extensor tendons within the retinacular compartment of the dog.

Antigen-induced proliferative synovitis was produced within the extensor retinacular compartment of one forepaw of young littermate dogs. The extensor tendons within the synovitis compartment were compared with the tendons in control compartments of the opposite forepaw. At 7 days following challenge, the tendons from the proliferative synovitis compartment showed increased uptake of [3H]proline at 5 min after pulse labeling. At 7, 14, and 28 days following challenge, the tendons within the proliferative synovitis compartment showed a significant increase in metabolic activity compared with control tendons after radioactive labeling for 6 h, with no associated difference in total collagen content of the control and synovitis tendons. These results indicate an increase in protein synthesis and degradation by the synovitis-surrounded tendons.