The Mechanism Of Celebrex For Chondrocyte Injury Of Osteoarthritis From The Perspective Of Aquaporins

Objective:Osteoarthritis is a common degenerative disease,which is a result of imbalance of degradation,synthesis and coupling among chondrocytes,cartilage matrix and subchondral bone.Functional changes in chondrocytes play an important role in the process of cartilage matrix degradation,and the important factor is to maintain stable chondrocyte function.By establishing a knee osteoarthritis model,this study is to observe its correlation with distribution and content of AQP1 and AQP3,and investigate the mechanism of action of Celebrex for anti-inflammation and detumescence of osteoarthritis from the perspective of aquaporins(AQPs)and chondrocyte injury.Methods and materials:1.Animal experiment:Male SD rats aged two months were randomized into three groups:blank control group(n = 15),osteoarthritis model group(n= 15)and Celebrex group(n= 15).Model was prepared by intra-articular injection of papain.After modeling,Celebrex group was given 17.85mg/(kg·d)of Celebrex by gavage.The blank control group and the osteoarthritis model group were given equivalent volume of normal saline by gavage once a day for four weeks.Serum IL-1? was assayed by ELISA.Histopathological changes of cartilage were observed by HE staining of the left knee joint,changes in matrical proteoglycan by toluidine blue staining,and changes in expression of AQP1 and AQP3 by immunohistochemistry(IHC).Changes in mRNA and protein expression of AQP1 and AQP3 were detected by real-time PCR and Western Blot after scraping the right articular cartilage.2.Cell experiment:SW1353 human chondrosarcoma cells were grown.Cell morphology was observed by toluidine blue staining and collagen ?immunocytochemistry.Cells were divided into three groups:negative control group,IL-1? treatment group,and IL-1?+ Celebrex treatment group.Cell survival rate was detected by CCK8.Cells were collected after interfering with IL-1? for 24 and 48 h,respectively.Changes in expression of AQP1,AQP3 and VEGF were detected by real-time PCR and Western Blot.Results:1.Serum IL-1? level elevated(P<0.01)four weeks after SD rats were modeled.Defective cartilage surface was visible.No nucleus was noted in local cartilage lacuna below the defect.Cartilage matrix staining was inhomogeneous and light.Matrical proteoglycan level decreased(P<0.01).Expression of AQP1 and AQP3 enhanced in chondrocytes of the radial and transitional zones(P<0.01);mRNA and protein expression of AQP1 and AQP3 was up-regulated,with a statistical significance.In the Celebrex group,serum IL-1? level decreased(P<0.05);the severity of cartilage injury improved;matrix staining was homogeneous;loss of proteoglycan retarded(P<0.01);expression of AQP3 was down-regulated in chondrocytes of the radial and transitional zones(P<0.01);mRNA and protein expression of AQP3 decreased(P<0.01);changes in AQP1 expression were not significant.2.Toluidine blue staining of SW1353 cells was bluish violet.Expression of cytoplasmic collagen II was positive.When treated with IL-1?,mRNA and protein expression of AQP1,AQP3,and VEGF was up-regulated(P<0.01,0.01 and 0.05,respectively).In the IL-1? + Celebrex treatment group,mRNA and protein expression of AQP3 was significantly down-regulated(P<0.01).Expression of AQP1 mRNA at 24 h and AQP1 at 48h was slightly down-regulated(P<0.05).Changes in mRNA and protein of VEGF were not significant.Conclusion:1.AQP1 and AQP3 play an important role in cartilage edema of osteoarthritis,especially the process of water transport.2.Celebrex can suppress expression of inflammatory cytokines,down-regulate expression of AQP1 and AQP3,retard loss of proteoglycan in the cartilage matrix,stabilize chondrocytes and improve cartilage diseases.3.IL-I? intervenes with abnormal expression of AQP1 and AQP3 by SW1353 cells.Celebrex can regulate such expression to stabilize chondrocytes.