Complete Freund's adjuvant induces an earlier and more severe arthritis in MRL-lpr mice

A study was performed on the effect of CFA on the spontaneous arthritis of MRL-lpr mice. The development of swelling and erythema was monitored for 1 mo after injecting 13- to 14-wk-old mice intradermally with CFA, at which time the histopathology of the joints and serologic responses to extracellular matrix proteins were investigated. In a series of six experiments, 67 to 82% of mice showed early clinical evidence of arthritis in contrast to the low percentage observed in control animals. Similarly, the histopathologic analyses on the CFA-injected mice indicated a significantly higher frequency of advanced histopathologic alterations, characterized by cartilage erosion and pannus formation. The serologic evaluation of the adjuvant-injected mice demonstrated a significant enhanced antibody production to type I and type II collagens, DNA, and the Mycobacterium tuberculosis-positive control. This reproducible adjuvant-enhanced model of murine arthritis will be extremely useful in evaluating experimental therapeutic regimes as the arthritis is initiated earlier and exhibits an enhanced frequency and severity compared with the spontaneous arthritis seen in MRL-lpr mice.