Eicosapentaenoic Acid suppresses the proliferation of synoviocytes from rheumatoid arthritis

Eicosapentaenoic acid (EPA) is essential for normal cell growth, and may play an important role in inflammatory and autoimmune disorders including rheumatoid arthritis. We investigate that EPA could suppress the proliferation of fibroblast like synoviocytes in vitro. We treated synoviocytes with 1 to 50 microM EPA and measured cell viabilities by the modified MTT assay. We sorted the number of them in sub G1 stage by fluorescence-activated cell sorting caliber. And we stained them by light green or Hoechst 33258, and investigate microscopic appearance. The cell viabilities were decreased at 30 microM, 40 microM, and 50 microM of EPA comparing to 0 microM of EPA. The half maximal concentration of synoviocytes inhibition was approximately 25 microM. At day 1 and day 3, cell number was also decreased at 50 microM EPA comparing to control. FACS caliber indicated the number of synoviocytes in sub G1 stage did not increase in each concentration of EPA. Hoechst staining indicated normal chromatin pattern and no change in a nuclear morphology both in EPA treated synoviocytes and in untreated synoviocytes. These findings suggest that EPA could suppress the proliferation of synoviocytes in vivo dose dependently and time dependently, however, the mechanism is not due to apoptosis.