Figure 3.

Effects of methotrexate on the expression of prostaglandin E₂ biosynthetic enzymes in rheumatoid synovium. Immunohistochemical evaluation of positive staining for microsomal prostaglandin E₂ synthase 1 (mPGES-1), cyclooxygenase 1 (COX-1), and COX-2 in synovial tissue biopsies before and 8 weeks after initiation of methotrexate treatment. Results are expressed as a percentage of the positive stained area versus the total tissue area.