Use of Freund's adjuvant arthritis test in anti-flammatory drug screening in the rat: value of animal selection and preparation at the breeding center.

The Freund's adjuvant technic, using killed Mycobacterium butyricum suspended in mineral oil, is a refined tool for anti-inflammatory drug evaluation. Its use has long been reserved for testing and not for screening due to technical problems in the preparation of valid animal models. After reviewing the methodology, the authors demonstrated that the availability of arthritic rats from a modern breeding center (Charles River France, SA, Elbeuf, France) make the procedure applicable to drug screening. This has both practical and economic advantages. The animals can be used as test organisms for drug evaluation 14 da after treatment. Three criteria for measuring the effectiveness of anti-arthritic drugs have been established: an arithritic index determined by examination of the 4 paws; changes in the erythrocyte sedimentation rate; and changes in levels of plasma fibrinogen. The curative activity of test substances can be evaluated by a single series of measurements of these 3 criteria after 14 da of treatment. This test was compared with 2 others; edema of the paw induced by the subcutaneous injection of kaolin or carrageenan, and was found to be superior.