We present a novel animal model for
rheumatoid arthritis induced with a well defined synthetic adjuvant oil,
pristane. Two weeks after a single
intradermal injection of 150 microliters of
pristane, the rats developed severe and chronic
arthritis. The
inflammation was restricted to the joints and involved pannus formation, major histocompatibility complex (MHC) class II expression, and T lymphocyte infiltration. The initial development as well as the chronic stage of
pristane-induced
arthritis was ameliorated by treatment with
antibodies to the
alpha beta-T-cell receptor showing that the disease is T cell dependent. Increased levels of
interleukin in serum was seen after
pristane injection but not during the chronic stage of
arthritis. Joint erosions were accompanied by elevated serum levels of
cartilage oligomeric matrix protein. Comparison of MHC congenic LEW strains showed that the severity and chronicity of
arthritis varied among the different MHC haplotypes. Rats with RT1f haplotype showed a significantly higher susceptibility to
pristane-induced
arthritis. A strong influence of non-MHC genes was also suggested by the variability of
arthritis susceptibility among different strains with the same MHC haplotype; the most susceptible background was the DA and the least susceptible was the E3.
Arthritis induced with a well defined nonimmunogenic adjuvant, with a disease course that closely resembles that of
rheumatoid arthritis, makes a suitable animal model for future studies of the pathology and genetics of
rheumatoid arthritis.