Dimethyl dioctadecyl ammonium bromide (DDA)-induced arthritis in rats: a model of experimental arthritis

A single intradermal injection of 2 mg of dimethyl dioctadecyl ammonium bromide (DDA) in phosphate buffered saline (PBS) could induce polyarthritis in both LEW and DA rats with low incidence and severity whereas 2 mg of DDA in incomplete Freund's adjuvant (IFA) could induce very severe polyarthritis with 100% incidence in LEW rats. Histology of DDA-induced arthritis (DIA) revealed cellular infiltration, synovial hypertrophy, development of granulation tissue, destruction of cartilage and bone deformation in the articular joints. Lymph node cells (LNCs) but not immunoglobulin fractions from the DIA rats successfully transferred the severe disease into the naive recipients. A challenge injection of DDA in IFA in the rats, which had recovered from the DIA, could reactivate the disease. It is thus concluded that DDA has arthritis-inducing ability in the rats which is potentiated by IFA and the DIA is a cell-mediated immune disease which might be a model of experimental arthritis.