Results The clinical parameters of arthritis progressively increased in CIA in all experimental times, demonstrating the greatest difference from other groups at 45 days after induction (clinical score: CO, 00±00; SA, 1.00±0.14; CIA, 3.28±0.41 p>0.05). The CIA animals had lower weights during all the experimentation periods with a difference of 6 % from CO at 45 days (p>0.05). CIA animals also demonstrated progressive decrease in distance walked, with a reduction of 54 % in 35 and 74 % at 45 days. Cytokine analysis identified significant increase in IL-6 serum levels in CIA than CO and SA in all experimental times. CSA of the myofiber of GA and TAwas decreased 26 and 31 % (p> 0.05) in CIA in 45 days after the induction of disease, respectively. There was significant and inverse correlation between the disease clinical score and myofiber CSA in 45 days (GA: r=−0.71; p=0.021). Conclusion Our results point to a progressive development of muscle wasting, with premature onset arthritis. These observations are relevant to understand the development of muscle loss, as well as for the design of future studies trying to understand the mechanisms involved in muscle wasting. As far as we are concerned, this is the first study to evaluate the relation between disease score and muscle atrophy in a model of arthritis
