The Characteristic Of Rat Adjuvant Arthritis And Collagen-induced Arthritis Models As Well As Expression Change Of β-arrestins In Synoviocytes From CIA Rats And The Effects Of Total Glucosides Of Paeony

OBJECTIVE To compare the characteristic of the complete Freund adjuvant (CFA) induced arthritis (AA) model and chicken typeⅡcollagen (CCⅡ) induced arthritis (CIA) model with physical signs, pathological and immunological changes. In order 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.METHODS CIA model in rats were induced by injection of chicken type II collagen (CCII) emulsion. AA model in rats were induced by injection of complete freund adjuvant. We observed these two models with polyarthritis symptoms, weight, paw swelling, polyarthritis index, incidence and histopathological changes. The change of IL-1,TNF-αand PGE2 production from peritoneal macrophage as well as the proliferation of T lymphocytes in AA rats were detected, for observating the effect of recombinant human interleukin-1 receptor antagon(RhIL-1Ra). We selected CIA model for the following study. 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. The polyarthritis index was scored. Lymphocytes and synoviocytes proliferation were determined by MTT assay. 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. Antibodies to CII were determined by enzyme-linked immunosorbent assay (ELISA).RESULTS(1) The characteristic of AA and CIA models The weight increasing stepped down in both models. Inflammatory reaction occurred on d10 in AA rats and reached to the peak on d20, then descented gradually. While the secondary inflammatory reaction occurred on d14 in CIA rats with paw swelling and articular histopathological changes, which got worse till d28 and lasted for a long time. We found that the incidence and the histopathological changes of CIA rats is similar as AA rats. IL-1,TNF-αand PGE2 production from peritoneal macrophage highly increased, while the proliferation of T lymphocytes inhibited in AA models, but RhIL-1Ra could restore this change. Anti-CⅡantibodies were only detectable in CIA rats, which indicated that there were humoral immunity and cellular immunity imbalance in CIA rats. Both models are ideal for RA researching and anti-inflammatory drug screening on account of the similar to human RA in clinical situation, immunological and pathological changes. (2) Effects of TGP on secondary inflammatory reaction, histopathology and immune functions in CIA ratsInflammatory reaction occurred on d14 after immunization. There was a marked secondary inflammatory response in CIA model, which accompanied with the paw swelling, pain, polyarthritic symptoms, the decrease of body weight and the increase of arthritis scores. The administration of TGP (25, 50, 100 mg·kg-1, ig, d14~28) inhibited the inflammatory response, Restored body weight and degraded arthritis scores of CIA rats. Compare to the normal rats, in CIA rats, the histopathology morphological of rats joints examination showed hyperplastic synovium, synovial lining hyperplasia inflammatory cells infiltration, pannus formation and destruction of the cartilage, and fatty changes in the synovial cells. The administration of TGP can ameliorate these changes, especially of TGP (100 mg·kg-1, ig, d14~28). Antibodies to CCII increased significantly in blood serum of CIA rats. TGP had no effect on the high concentration of antibodies to CII. The ConA-induced T lymphocyts and LPS-induced B lymphocyts proliferation were both increased in CIA rats, while could be inhibited by TGP (25, 50, 100mg·kg-1, ig, d14~d28). Fibroblast-like synoviocytes (FLS) proliferation could be reduced by TGP (50, 100mg·kg-1, ig, d14~d28).(3) The expression change ofβ-arrestins in synoviocytes of CIA rats and the effects of TGP on itAt the inflammatory process (d14, d28 after immunization), we observed a profound up-regulation ofβ-arrestins in synoviocytes from CIA rats and during the remission phase (d42 after immunization),β-arrestins'expression is returning to baseline levels. TGP (50, 100mg·kg-1, ig, d14~d28) could reduce the expression ofβ-arrestins greatly. This detection showed thatβ-arrestins may become an important molecular target in the pathogenesis of RA. G-protein function in synoviocytes was imbalance, and TGP can regulate G-protein-cAMP signaling by effecting of GRK/arrestin desensitization mechanisms.CONCLUSIONS1. Both AA and CIA models are ideal for RA researching and anti-inflammatory drug screening on account of the similar to human RA in clinical situation, immunological and pathological changes.2. TGP has an improvement effects on polyarthritis, paw swelling, ang articular histopathological changes in CIA rats, which is related to its modulating immune function, inhibition synoviocytes proliferation.3. An inflammatory process in vivo induces an up-regulation ofβ-arrestins in synoviocytes from CIA rats while TGP can inhibit this change, which might be one of the important mechanisms for TGP to produce a marked therapeutic effect on RA.