Adjuvant polyarthritis and the response of air pouch lining cells

The influence of adjuvant polyarthritis on subcutaneous air pouches in rats was examined in the light of reports of the resemblance of their cavity lining to normal synovium. Marked macroscopic and microscopic changes were observed. These included thickening of air-pouch wall, hyperplasia of lining cells, infiltration of inflammatory cells, fibrosis, and the production of an effusion in the cavity; such changes are comparable to the proliferative synovitis reported in arthritic joints of diseased animals. However, whereas talus and patella cartilage were affected by the disease, these and femoral-head cartilage seemed to be relatively spared when implanted in air pouches of adjuvant-diseased rats even after a massive inflammatory response was elicited in the cavity following challenge with tuberculin. In conclusion, the present study demonstrates the generalized nature of adjuvant disease and confirms the lack of association between inflammation and cartilage destruction.