Suppression of arthritis progression with lutein extracted from Tagetes erecta in collagen-induced arthritis model rats

Background: Chronic arthralgia and arthritis are the most common causes of activity limitation and disability among middle-aged and older adults. Rheumatoid arthritis is a persistent inflammation of the synovium of the joints, leading to destruction of the surrounding bone and cartilage and ultimately joint deformities. Several studies reported that carotenoid intake, including lutein, was associated with a decreased risk of rheumatoid arthritis. We examined the effects of lutein extract (LE) from Tagetes erecta on inflammatory suppression in the collagen-induced arthritis (CIA) model rat. Method: CIA model rats were induced by injection of emulsion containing bovine type II collagen and Freund’s incomplete adjuvant to DA/slc male rats. The study was designed with four experimental groups referred to as: normal, vehicle, ibuprofen (30 mg/kg) and lutein (1.5mg lutein/kg). Test substances were administrated orally after immunization for 31 days every day. Results: Arthritis scores and paw swelling were significantly suppressed by LE or ibuprofen administration. Histopathological analysis showed that LE suppressed synovial fibroblast proliferation, plasma cell accumulation, pannus formation and new bone formation in the hind paw, although no changes in inflammation and cartilage metabolism biomarkers in plasma were detected after LE administration. Furthermore, proliferation of rabbit synovial cells (HIG-82) was inhibited by the addition of lutein. Conclusion: We provide direct evidence that lutein extract suppresses inflammation in the collagen-induced arthritis model rat. It is expected that lutein may play a beneficial role in rheumatoid arthritis.