Antirheumatic drug profiles evaluated in the adjuvant arthritis of rats by multiparameter analysis

Freund's adjuvant arthritis (FAA) in susceptible rats (male, Lewis strain) is a well-established experimental model of rheumatoid arthritis to evaluate inherent drug properties, i.e. anti-inflammatory and/or immunosuppressive/immunomodulatory properties which are only ascertained by combining multiple parameter analysis. We employed a synoptic multiparametric evaluation system for the multifaceted FAA, a so-called "spider scheme", to facilitate a more rapid and easier comparison of qualitative and quantitative drug properties by visual display than that achieved by mere tabulation of the data. The spider scheme comprised six well-established parameters to evaluate the FAA disease (primary and secondary hind paw swelling, arthritic index which included macroscopic alterations of non-injected paws, nose, ears and tail, body weight changes and relative organ weights of thymus and spleen). By calculation of an index as a percent change in comparison to control and untreated diseased animals, the degree of improvement or impairment of the FAA by a tested compound could easily be entered into the spider scheme. The FAA parameter spider scheme clearly differentiated the most beneficial immunomodulatory properties of cyclosporin A from those of the immunosuppressive agents dexamethasone and cyclophosphamide as well as from the mere anti-inflammatory cyclooxygenase inhibitors. Among this latter class of non-steroidal anti-inflammatory compounds, a similar profile was demonstrated for indometacin and diclofenac, as well as for tenidap, which is claimed to have cytokine-modulating properties, as reflected by the reduction of acute-phase proteins in patients with rheumatoid arthritis. Yet, in this FAA model, with tenidap, no additional qualitative drug properties could be discerned.(ABSTRACT TRUNCATED AT 250 WORDS)