Background:

Rheumatoid arthritis is a classic autoimmune disease in which elevated immune responses to collagen have been reported. Since its initial discovery, the animal model of collagen-induced arthritis has demonstrated many parallels to human rheumatoid arthritis. Trentham et al. describes the method of inducing and evaluating arthritis in this animal model. It has been predictive in the past of subsequent clinical outcome in patient trials. 

 

Study Design:

Thirty rats were randomized into 3 groups (n=10/group): control (water), 7 mg daily of immune egg, and 350 mg daily of immune egg. Results were combined from three experiments [n=60]. Rats were gavaged with test article for 7 days prior to intradermal challenge with type II collagen and for 16 days after induction. Starting at day 10 following type II collagen challenge, and daily thereafter for ~14 days, rats were clinically evaluated in a blind manner for rat paw erythema and paw swelling of limbs. A summation of scores based on the degree of incidence and severity of erythema were used as an index (AI). In addition anti-type II collagen autoantibodies were assayed using an ELISA.

 

Results:

At day 21 the AI was significantly reduced in animals that received 350 mg daily of immune egg as compared to the control group. In addition, the incidence of erythema was significantly suppressed in the high-dose group compared to the low dose and control groups. The onset of erythema was also delayed in the high dose groups compared with the control group. The results from animals on lower doses of egg did not differ significantly from the controls. Type II collagen autoantibodies were also reduced in animals on higher doses of immune egg.