Expression Of Chemokine RANTES In Synovium Of Rat Arthritis Model

Objective:To oberserve the expression of Regulated upon Activation Normal T cell Exprssed and Secreted(RANTES) in rat experimental arthritis model and evaluate the effect of methotrexate (MTX) on the expression of RANTES.Methods:Thirty male Wistar rats were randomly divided into3 groups(each 10), namely the model control group, the given medicine group and the normal control group,then we established a model of collagen-induced arthritis. The rats of the given medicine group that were induced successfully were given muscular injection of MTX with a single dose of 0.75mg/kg after 28 days,hereafter the injection were given for four weeks every week once.We evaluate arthritis index(AI) on the rats of 3 groups after four weeks. We narcotized all rats on the 56th day, then we draw blood from abdominal aorta. IL-1β and TNF-α level were measured with radioimmunoassay(RIA). IgG,IgA and IgM level were determined by immunodiffusion.We took down the double side malleolus joint,then we handle joints with decalcification. Each rat were evaluated for the pathological score.The expression of RANTES of synovium was detected with immunohistochemistry.The intensity of RANTES was analyzed bycomputerized imaged system.Results: 1. The AI of the given medicine group was 2.90±0.74, and the AI of the model control group was 9.80±1.62.There was significant difference between the given medicine group and the model control group in AI. (P<0.05)2. The level of TNF-α in the given medicine group was significant lower than that in the model control group.(P<0.05)There was no significant difference between the given medicine group and the model control group in the level of IL-1β and IgA.(P>0.05)The level of IgG and IgM in the given medicine group was significant lower than that in the model control group. (P<0.05)3.The pathological score in the model control group was significant higher than that in the given medicine group. (P<0.05)4.The average grey scale of the model control group was 103.0319±3.9212,and that of the given medicine group was 135.9531±3.7206. The positive area percentage of the model control group was 37.66±2.7486,and that of the given medicine group was 16.12±2.3631. There was significant difference between the given medicine group and the model control group in the average grey scale and the positive area percentage. (P<0.05) 5 .The pathological score in rat experimental arthritis model showed a positive correlation with AI (r=0.996,P<0.01),TNF-α(r=0.979,P<0.01),IL-1β(r=0.903,P<0.01),IgG(r=0.951,P<0.01),IgA(r=0.858,P<0.01)and IgM(r=0.951,P<0.01).The grey scale of RANTES expression showed a negative correlation with AI(r=-0.998,P<0.01),TNF-α(r=-1.000,P<0.01),IL-1β(r=-0.999,P<0.01),IgG(r=-1.000,P<0.01),IgA(r=-0.615,P<0.01)IgM(r=-0.998,P<0.01)and the pathological score(r=-0.991,P<0.01). Conclusion: RANTES may play an important role in rat experimental arthritis . MTX may protect joints through reducing the expression of RANTES.