IMMUNOPHARMACOLOGICAL STUDIES ON COLLAGEN-INDUCED ARTHRITIS IN DARK AGOUTI (DA) RATS

Dark Agouti (DA) and Lewis rat strains were tested for susceptibility to collagen-induced arthritis (CIA) and for development of cellular an d humoral immune responses to type II collagen (CII). All of the DA ra ts developed arthritis following a single intradermal injection of mor e than 20 mu g of CII (130-150 mu g/kg rat weight) and showed a swelli ng rate of more than 100% in the hind paws. The swelling rate showed l ittle deviation among the animals. There was a strong correlation betw een the severity of the arthritis and the strength of the immune respo nse to CII in DA rats with CIA. Following immunization with even 800 m u g of CII (3.8-4.2 mg/kg rat weight), Lewis rats showed a maximum rat e of hind paw swelling of only 45%. In the pharmacological studies, pr ednisolone, indomethacin, FK-506 and mizoribine all suppressed arthrit is in DA rats. These findings suggest that DA rats are more susceptibl e to CIA than Lewis rats and that CIA in DA rats as well as in Lewis r ats is serviceable as an experimental animal model of rheumatoid arthr itis.