To investigate the effects and potential mechanism of L161982 (a kind of EP4 antagonist) on the collagen-induced arthritis (CIA) mice model. The CIA mice model were first established by immunizing with Chicken Type II Collagen on DBA/1 mice. The CIA groups were administered once a day for 2 weeks with either 5 mg/kg L161982 by intraperitoneal injections (IP), 200 U celecoxib by intragastrical injections, or 100 μl PBS (IP). |