Preventive effect of FTY720 on osteoporosis in collagen-induced rheumatoid arthritis mice

Abstract

Objective To observe the preventive effect of FTY720 on osteoporosis in type 2 collagen-induced rheumatoid arthritis (RA) mice. Methods The RA osteoporosis model was induced with type 2 collagen in mice, and 10 weeks later, the animals were grouped. Mice were administrated by 0.25, 0.50, 1.00 mg/kg FTY720 for 8 weeks respectively. Body weight, RA score, calcium and phosphorus contents, bone mineral density, and morphology were observed in mice with RA osteoporosis. Results FTY720 can reduce the arthritis score of RA mice with administration 6-8 weeks (P=0.000-0.038). After 8 weeks of administration, arthritis score of model group is (10.25±0.45) points, arthritis score of high dose group decreased to (7.75±0.25) points. FTY720 can reduce the swelling degree with administration 5-8 weeks (P=0.008-0.043). Serum calcium level of high dose group was significantly increased at 8 weeks (P=0.033), content of calcium in urine of medium and high dose group was significantly reduced (P=0.000). The bone mineral density of tibia and femur was significantly increased in high dose group (P=0.013-0.019). Meanwhile FTY720 improve the cartilage damage and the destruction of the trabecular structure in RA mice. Conclusion FTY720 can inhibit the occurrence of osteoporosis in RA mice. Key words: FTY720; Rheumatoid arthritis; Osteoporosis