Lactobacillus casei-induced polyarthritis in Lewis rats: histopathological scoring system for evaluation of anti-rheumatic drugs.

A histopathological scoring system which grades drug effects on cellular infiltration, pannus formation, cartilage degradation and bone resorption in L. casei-induced polyarthritis in rats is described. Reference anti-rheumatic and anti-inflammatory agents administered on days 2-60 after induction of arthritis were evaluated for effects on paw swelling weekly and graded histopathologic changes on day 60. This animal model affords a tool to evaluated therapeutic agents on the joint destruction resulting from chronic inflammation.