Paeoniflorin Ameliorates Collagen-induced Rheumatoid Arthritis In Rats: By Regulating ROCK/NF-?B Pathway

Objective: To investigate the mechanism of Paeoniflorin(PF)on ROCK/NF-?B pathway for rheumatoid arthritis(RA).To provide a experimental basis for the clinical application of paeoniflorin and a novel therapeutic for rheumatoid arthritis.Methods: Take Male Wistar rats to carry out the experiment.Randomly divide them into the normal group,the model group,the high-,low-dose PF groups(50 and 100mg/kg).Rats were induced to arthritis by intradermal injection of bovine type II collagen in Freund's complete adjuvant except the ones in the normal group.Later,the CIA rats were given orally administered PF(50 and 100mg/kg)once a day from the day 21.The rats were sacrificed after 14 days of oral administration,the serum and the joint synovial tissue of rats were removed and analyzed.The severity of the disease and the contents of pro-inflammatory cytokines,including tumor necrosis factor alpha(TNF-?),interleukin-1beta(IL-1?),and interleukin-6(IL-6)in serum as well as p-NF-?B p65 and p-MYPT1 in the joint synovial tissues were detected.Results:1.CIA rats showed progressing joints swelling and even along with movement disturbance.Compared with the model group at corresponding period,all of the PF groups had improvement on rats`activity,joints swelling and movement disturbance,especially for the high-dose of PF.2.A significant reduction in paw edema and redness was noticed with oral administration of PF at 50 and 100 mg/kg compared to the CIA group.After a two weeks of treatment with PF at 50 and 100 mg/kg,the clinical arthritic score(p < 0.05)and paw swelling(p < 0.05)decreased significantly in a dose-dependent manner as compared with that of the CIA group.3.Pro-inflammatory cytokines IL-1?,IL-6,and TNF-? in serum were significantly increased when compared with the normal group.However,after a two weeks of treatment with PF(50 and 100 mg/kg),IL-1?,IL-6,and TNF-? levels were reduced compared to the CIA rats(p < 0.05),especially for the high-dose of PF group.4.According to the results detected by IH,compared with the normal group,the CIA group showed higher of p-NF-?B p65?p-MYPT1 proteins obviously(p < 0.05).Compared with the model group,the PF group showed lower of p-NF-?B p65?p-MYPT1 proteins(p< 0.05),especially for the high-dose of PF.5.According to the results of H&E staining,the normal group presented clear and smooth tissues,without inflammatory cell infiltration.The CIA group demonstrated obvious hyperplasia of the synovial tissues,destruction of the articular cartilage,a narrowed articular cavity,and the infiltration of many inflammatory cells.PF 50 and 100mg/kg remarkably inhibited the hyperplasia of the synovial membrane and significantly reduced the infiltration of inflammatory cells and cartilage injury compared to the CIA group.Conclusion:1.The results demonstrated that PF treatment significantly ameliorated the symptoms in CIA rats,reduced the levels of pro-inflammatory cytokines and paw swelling,down-regulated the expressions of p-NF-?B p65 and p-MYPT1 compared to those in the CIA group.2.The present results revealed that PF could effectively improve collagen-induced RA in rats by inhibiting Rho kinase activation in joint synovial tissues,in turn down-regulating expression of p-NF-?B p65 and reducing contents of pro-inflammatory cytokines.