Time course of arthritis-related changes in rats with antigen-induced-arthritis. (a) Joint circumference of rat knees is estimated from joint width (as described in Materials and methods). (b) Hind-paw weight distribution of arthritic rats is compared with that of saline-injected controls. Data are expressed as percentage of weight distribution onto the right knee (sensitized with mBSA or saline-injected for control rats). (c) Proteoglycan synthesis in patellar cartilage is measured by Na235SO4 incorporation. Data are expressed as the percentage of change in 35sulfate incorporation in the central part of the patella. Data are mean ± standard error of the mean from 28 rats (a,b) or five samples (c). *P < 0.05 sensitized versus saline-injected knee. ≠P < 0.05 arthritic versus saline-injected rats. mBSA, methylated bovine serum albumin.