Pain: noxious stimulus, Paw-pressure test. Monoarthritis was induced by injection of MIA into the knee joint. On day 1, 2 mg MIA in 25 μl saline were delivered in the left (ipsilateral) articular cavity. Paw pressure test was performed on day 14. Collagen was suspended in 1% CMC and daily administered p.o. starting on the 1th day suddenly after MIA. Control animals were treated with vehicle. Each value represents the mean of 12 rats performed in 2 different experimental set.*P < 0.01 vs the contralateral paw; §P < 0.05 and ^P < 0.01 vs the MIA + vehicle treated rats.