Articular pain, PAM test. The effect of collagen (daily administered starting on the 1th day) on MIA-induced articular damage was evaluated on day 14. Data are expressed as the difference between the force tolerated on the knee joint contralateral to the injury and the force tolerated on the ipsilateral one. Control animals were treated with vehicle. Each value represents the mean of 12 rats performed in 2 different experimental set. *P < 0.01 compared to vehicle + vehicle rats; §P < 0.05 and ^P < 0.01 compared to MIA + vehicle treated rats.