The Expression Changes Of β-arrestins In Synoviocytes From CIA Rats And Human And The Effects Of Total Glucosides Of Paeony And Paeoniflorin

OBJECTIVE To elucidate the pathogenesis of rheumatoid arthritis (RA) and the therapeutic mechanism of total glucosides of paeony (TGP), we investigated the expression change ofβ-arrestins in synoviocytes from CIA rats and TGP administrated rats. The study was also to investigate the expression change ofβ-arrestins in human fibroblast-like synoviocytes (FLS) induced by pro-inflammatory cytokines such as IL-1βand the therapeutic mechanism of Paeoniflorin(Pae),and the relationship betweenβ-arrestin2 and ERKMETHODS CIA model in rats were induced by injection of chicken type II collagen (CCII) emulsion. TGP (25, 50, 100mg·kg-1·d-1) was administrated intragastric to CIA rats during d14~d28. Hind paw volumes of rats were measured by volume meter. Synoviocytes proliferation were determined by MTT assay. Antibodies to CII were determined by enzyme-linked immunosorbent assay (ELISA).Pathological changes in synovium of joint were observed by light microscope. The expression ofβ-arrestins in synoviocytes from CIA rats was measured by western blot. We investigate the expression changes of cAMP,β-arrestins and the activities of PKA and the effect of Paeoniflorin in human fibroblast-like synoviocytes (FLS) induced by IL-1βby radioimmunoassay and western blot.RESULTS(1) The expression changes ofβ-arrestin1 andβ-arrestin2 in synovial tissue of CIA ratswe investigatedβ-arrestins expression in synovial tissue in CIA rats ,and it was found that there were no significant differences in the expression ofβ-arrestin1 on different days,however the expression ofβ-arrestin2 on day 21,28 after immunization increased apparently,which reached its peak.The level ofβ-arrestin2 increased significantly from day14 ,when it was at the onset of the inflammation of CIA ,and reached its peak on day28,which was in accord with the peak of the inflammation of CIA.(2) The expression ofβ-arrestin 2,cAMP accumulation and the activities of PKA in human FLS induced by IL-1βWe found that the activities of PKA and cAMP accumulation increased significantly in human FLS on 4h after induced by IL-1β,and cAMP accumulation decreased especially on 24hWe found that the expression ofβ-arrestin2 increased significantly on 24h after induced by IL-1β,further studies found that U 0126 (25 and 50μM) decreased the expressions ofβ-arrestin 2 induced by IL-1βin human FLS.(3) Effects of TGP on CIA rats and the influence of TGP and Pae on the expression ofβ-arrestin2The administration of TGP (25, 50, 100 mg·kg-1, ig, d14~28) inhibited the inflammatory response, degraded the paw swelling. Antibodies to CCII increased significantly in blood serum of CIA rats,TGP (25, 50, 100 mg·kg-1)could reduce the high concentration of antibodies to CII. Fibroblast-like synoviocytes (FLS) proliferation increased significantly in CIA rats, while could be inhibited by TGP (50, 100mg·kg-1, ig, d14~d28). TGP (50, 100mg·kg-1, ig, d14~d28) could reduce the expression ofβ-arrestin2 greatly in synovial tissue of CIA rats.Pa(e10-5,10-6,10-7 mol·L-1)in vitro could reduce the high expression ofβ-arrestin 2 in CIA rats and human FLS induced by IL-1β.CONCLUSIONS1. An inflammatory process in vivo induces an up-regulation ofβ-arrestin2 in synovial tissue from CIA rats.2. The expression ofβ-arrestin 2 increased significantly after induced by IL-1βin human FLS;U 0126 (25 and 50μM) decreased the expressions ofβ-arrestin 2 induced by IL-1βin human FLS,which indicated that phosphorylation of ERK perhaps increased the expression ofβ-arrestin 2.3. TGP can inhibit the overexpression ofβ-arrestin 2 in vito,and Pae(10-5,10-6,10-7 mol·L-1)in vitro could reduce the high expression ofβ-arrestin 2 in CIA rats FLS and human FLS induced by IL-1β,which reduced the overdesensization of GPCRs and inhibited synoviocytes proliferation.