细胞周期蛋白依赖性激酶7在骨性关节炎软骨中的表达及其意义

Expression and significance of cyclin-dependent kinase 7 in osteoarthritic cartilage

目的:探讨细胞周期蛋白依赖性激酶7(CDK7)在骨性关节炎(OA)软骨组织中的表达及其意义。方法:取10例行全膝关节置换术的OA患者(实验组)和3例行下肢截肢手术患者(对照组)的软骨组织,通过番红O染色、免疫组化及Western blotting检测CDK7在两组软骨中的表达。用体外培养的人软骨肉瘤细胞(SW1353)建立不同病变程度的OA细胞模型,通过Western blotting检测CDK7及炎症因子白细胞介素-6(IL-6)、诱导型一氧化氮合酶(iNOS)的表达变化。用CDK7 siRNA来抑制OA细胞模型中CDK7的表达,Western blotting检测此时IL-6、iNOS的表达变化以及核因子κB(NF-κB)通路活性因子p-p65、p-IκBα、IκBα的表达变化。结果:CDK7在OA软骨中的表达高于正常软骨(P<0.05)。随着OA细胞模型病理程度加重,CDK7、IL-6、iNOS的表达呈现增高趋势(P<0.05)。当CDK7的表达受到抑制时,IL-6、iNOS的表达降低(P<0.05),提示炎症反应减弱;p-p65、p-IκBα的表达降低(P<0.05),IκBα的表达升高(P<0.05),提示NF-κB活性减弱。结论:OA患者关节软骨CDK7的表达较正常人升高,提示CDK7在OA的病理过程中可能起重要作用。CDK7可能是通过促进NF-κB通路的活化来促进OA软骨的炎症反应。

Objective: To investigate the expression and significance of cyclin-dependent kinase 7(CDK7) in osteoarthritis(OA) cartilage. Methods: The cartilage tissues of 10 patients with OA who underwent total knee arthroplasty(experimental group) and 3 patients with lower extremity amputation(control group) were compared. The expression of CDK7 in cartilage was compared by Safranin O staining, immunohistochemistry and Western blotting assay. Human chondrosarcoma cells(SW1353) cultured in vitro were used to establish OA cell models with different degrees of disease, and the expression changes of CDK7 and inflammatory factors interleukin6(IL-6) and inducible nitric oxide synthase(iNOS) were detected by Western blotting. CDK7 siRNA was used to inhibit the expression of CDK7 in OA cell model. The expression of IL-6 and iNOS and the expression of nuclear factor-kappa B(NF-κB) pathway activity factors p-p65, p-IκBα and IκBα were detected by Western blotting. Results: The expression of CDK7 in OA cartilage was higher than that of normal cartilage(P<0.05). The expression of CDK7, IL-6 and iNOS increased with the pathological degree of OA cell model aggravated(P<0.05). When the expression of CDK7 was inhibited, the expression of IL-6 and iNOS decreased(P<0.05), suggesting that the inflammatory response was weakened;the expression of p-p65 and p-IκBα was decreased(P<0.05), and the expression of IκBα was increased(P<0.05), suggesting that NF-κB activity was attenuated. Conclusion: The expression of CDK7 in articular cartilage of patients with OA is higher than that of normal people, suggesting that CDK7 may play an important role in the pathological process of OA. CDK7 may promote the inflammatory response of OA cartilage by promoting activation of the NF-κB pathway.