Knee joint 99mTc-pertechnetate (Tc) uptake during zymosan-induced arthritis (ZIA). Tc uptake was assessed at different time points after injection of zymosan A in (a) ob/ob (black symbols) and +/? (white symbols) mice (6 hours, 24 hours, day 3: n = 9–10 per group; day 7: n = 5 per group), and in (b) db/db (black symbols) and db/+ (white symbols) mice (n = 6 per group). Results are expressed as the ratio of Tc uptake in the inflamed to that in the control knee joints. A ratio greater than 1.1 indicates inflammation. In panel (a) data shown for each time point are means ± SEM in one representative experiment out of five; in panel (b) data shown are means ± SEM in one experiment. Joint swelling was significantly greater on days 3 and 7 in ob/ob as compared with +/? mice, and in db/db as compared to db/+ mice (*P < 0.01).