Basic assessment of experimental arthritis in rats

Following the induction of CIA, all animals were observed continuously to assess the development and progression of CIA. The severity of CIA was periodically evaluated based on paw swelling and arthritis score. Paw edema of rats was evaluated by measuring the volume of the right hind paw and a water displacement method was employed for this purpose. The arthritis score was assessed based on the independent observations of three scholars. Each paw was scored on a scale of 0–4, therefore meaning that the highest total score was 16. The assessment criteria were as follows: 0= no edema or any visual changes; 1= slight edema and limited erythema; 2= light edema and erythema; 3= obvious edema and significant erythema; and 4= severe edema and extensive erythema. To investigate the effects of treatments on radiological changes in the joints of CIA rats, lateral and frontal digital radiography (DR) examinations of the hind limbs were carried out one day ahead of sacrifice.