Adjuvant polyarthritis and the pseudosynovitis.

The cavity lining of a six day old subcutaneous air pouch in rats resembles normal synovium in morphology and responds in a comparable manner during development of polyarthritis. The ability of newly formed pouches (one and two days old) to respond similarly to polyarthritogen was examined here. Positive macro and microscopic changes similar to those seen in the six day old pouch were observed in rats previously inoculated with adjuvant. The intensity of some of these changes varied between pouches. The results of this study indicate that the adjuvant induced air pouch reaction does not depend on the presence of synovial-like lining for its production.