Effect Of G Protein-coupled Receptor Kinases In Signal Transduction Of Synoviocytes From Rats With Collagen-induced Arthritis And The Effects Of Total Glucosides Of Paeony And Paeoniflorin

OBJECTIVE To investigate the expression changes of GRKs in synovium from CIA rats during the inflamation and the effects of TGP. Then we clarified the expression of GRKs in synoviocytes from CIA rats and the effects of Pae, and we attempted to investigate the role of GRK2 playing in G-Protein signal transduction pathways of synoviocyte and the effects of Pae. And further to analyze the relationship between the effects of Pae on CIA rats and its relative mechanisms by which Pae affected the process of synoviocytes through these signal transduction pathways.METHODS The model of rat CIA was induced by injection of chicken typeⅡcollagen(CCⅡ) emulsion. TGP(25,50,100 mg·kg^-1, ig, d14-d28) was administrated intragastric to CIA rats . Hind paw volumes of rats were measured by volume meter. Pathological changes in synovium of joint were observed by light microscope. The expression of GRKs in synoviocytes from CIA rats was measured by western blot. The expression change of cAMP was investigated by radioimmunoassay, and the activities of PKA was measured by luminescent kinase assay.RESULTS(1)Expression changes of GRKs in synovium from CIA rats during the inflamation and the effecrs of TGPInflammatory reaction occurred on d14 after immunization. There was a marked secondary inflammatory response in the models, which accompanied with paw swelling, pain, polyarthritis, decrease of body weight, and the development of inflammatory lesions. Compared with the normal rats, in CIA rats, the histological morphological examination of rats knee joints showed hyperplastic synovium, synovial lining hyperplasia, inflammatory cells infiltration, pannus formation and destruction of the cartilage, and fatty changes in the synoviocytes. At the inflammatory process (d14～d28 after immunization), we observed a profound up-regulation of GRKs'in synovium from CIA rats and during the remission phase (d46 after immunization), GRKs'expression is returning to baseline levels. TGP (25,50,100 mg·kg-1, ig, d14-28) diminished the right hind paw swelling and polyarthritic symptoms. TGP (25,50,100 mg·kg-1) the expression of GRK5,GRK6 in synovium from CIA rats. TGP(100 mg·kg-1)could decrease the expression of GRK2.(2)Expression of GRKs in synoviocytes from CIA rats and the effecrs of PaeExpression of GRK2,GRK5,GRK6 in synoviocytes from CIA rats was increased, Pae(10-5,10-6,10-7,10-8 mol·L^-1)in vitro could suppress the expression of GRK2,GRK5,GRK6 in synoviocytes from CIA rats.(3)Role of GRK2 in GPCR-AC-cAMP signaling transduction and the effects of PaeLevel of cAMP and activity of PKA increased in synoviocytes from CIA rats after GRK2 inhibito(rMethyl 5-[2-(5-nitro-2-furyl)vinyl]-2-furoate,C12H9NO6)were given. Pae(10-5,10-6,10-7,10-8 mol·L^-1) may decrease the level of cAMP and Pae(10-5,10-6mol·L^-1)might suppress the activity of PKA.CONCLUSIONS (1)An inflammatory process in vivo induces an up-regulation of GRKs in synovium and synoviocytes from CIA rats. The up-regulation of GRKs may play an important role in proliferation of synoviocytes from CIA rats.(2)TGP can diminish the paw swelling and polyarthritic symptoms, and decrease the expression of GRKs in synovium from CIA rats.In Synoviocytes of CIA rats,Pae may suppress the up-regulation of GRK2,GRK5 and GRK6,and at the same time recover the disorder of desensitization induced by GRK2 inhibitor. Which indicates that TGP,Pae can suppress over-desensitization of synoviocytes from CIA rats, and regulate desensitization of synoviocytes, which may be one of the important mechanisms for the effects of Pae on synoviocytes.