| Osteoarthritis (OA) is a degenerative joint disease in the aging population,which is characterized by cartilage degradation and osteophyte formation.The total prevalence rate of radiographic knee OA in 6 cities of China was 28.7%.Several factors play roles in the pathogenesis of osteoarthritis,including age,sex,genetics, obesity and occupation.The traditional view think that the progression of OA is affected by proinflammatory factors such as IL-1,IL-6,TNF-αand proteinases such as MMPs.However,accumulating evidence using experimental OA models in knochout mice has not produced supporting evidence.The mechanism of OA pathogenesis remains undefined.Recent findings show that Wnt/β-catenin signaling may plays an important role in the development of OA.Animal experiments showed that overexpression of P-catenin in articular chondrocytes leads to the development of an OA-like phenotype.To investigate if Wnt/β-catenin signaling upregulate in the articular chondrocytes of OA patients,we test the MMP-13 andβ-catenin protein levels and the expression of chondrocyte maturation marker genes in the articular cartilage of samples from OA patients and control group.This study provides evidence about the role of Wnt/β-catenin signaling on the development of OA.Objectives1. To investigate the levels of MMP-13 and P-catenin in cartilage chondrocytes of OA patients and control group.2. To investigate the expression of BMP-2,COL-X and MMP-13 genes in cartilage tissue of OA patients and control group.MethodsOA group:articular cartilage samples were obtained from patients undergoing total knee arthroplasty (42 cases).Control group:the articular cartilage samples were provided by department of Anatomy in Tianjin Medical University (8 cases). The articular tissues were fixed and embedded in paraffin.The sections were stained with Hematoxylin and Eosin(HE),Safranin O/Fast Green (SO/FG) and Alcian blue/orange G(AB/OG).The samples of articular cartilage were divided into three groups by using the modified Mankin score.There were control group,mild OA and moderate OA group.The levels ofβ-catenin and MMP-13 were detected by immunohistochemistry staining,and using chi-square test or Fisher exact probability for statistic analysis.Total RNA was extracted from articular cartilage tissues of OA paitents and control group.Real Time reverse transcriptase polymerase chain reaction(RT-PCR) was performed to test the expression of BMP-2,COL-X and MMP-13 and also the expresssion ofβ2M was tested for reference.The data was analysed by SPSS statistics 17.0.Results1. Articular cartilage destructions were found in OA patients,complete loss of articular cartilage and chondrocytes premature,hypertrophy, cell cloning, or tidemark breaking and new blood vessel invasion were also found in these patients.2. The result of (β-catenin immunohistochemistry showed negative in control group, 9 positive in mild OA and 7 positive in moderate OA group.The result of MMP-13 immunohistochemistry showed one positive in control group,14 positive in mild OA and 21 positive in moderate OA group.3. The result of Real Time RT-PCR showed that the expression levels of BMP-2, COL-X and MMP-13 were significantly increased in mild OA group(6.64-,8.12-and 9.92-fold) than control group(P＜0.01),the expression levels of that genes were increased in moderate OA group(2.21-,2.81-and2.46-fold) than control group(P<0.01).Conclusions1. The protein levels ofβ-catenin and MMP-13 were significantly increased in the cartilage chondrocyte of OA patients.2. Expression of chondrocyte maturation marker genes,such as BMP-2,COL-X and MMP-13 were significantly increased in articular cartilage of OA patients.3. These results establish a strong association between Wnt/β-catenin signaling and human OA.
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