Wnt/β-Catenin经典信号途径在儿童大骨节病关节软骨损伤中的作用机制研究

Kashin-Beck disease (KBD) is a chronic, endemic disease that mainly occurs in children, and it severely harms the health of residents who living in endemic areas. Although KBD has been studied for many years, its aetiology and pathogenesis remain uncertain. Recent studies found that Wnt/β-catenin canonical signal pathways play a key role in occurrence and development of cartilage diseases and osteoarthritis. Although KBD is a special type of osteoarthrosis, its etiology and affected populations are different from osteoarthrosis. So, whether Wnt/β-catenin canonical signal pathways play role in the process of articular cartilage injury of children KBD need further study. In order to explore the molecular mechanism of articular cartilage injury in pediatric KBD patients, this project looks Wnt/β-catenin signaling pathways as a breakthrough point. On the one hand, to detect the levels of downstream target gene product (MMP-13、BMP-2 and WISP-1) and to analyze the relationship between downstream target gene product and cartilage metabolites in order to explore effects of Wnt/β-catenin canonical signal pathways on the metabolism of cartilage ECM. On the other hand, to observe the apoptosis of cartilage cells and measure the levels of apoptosis factor and related apoptosis proteins, to discuss the effects of Wnt/β-catenin canonical signal pathways on cartilage cell apoptosis. Field trial and animal experiments were combined in this study and the results of animal experiments can verify and supplement the results of field trial. This study will further clarify the pathogenesis of KBD. At the same time, it can provide the theoretical basis for the establishment of new treatment targets of KBD.

大骨节病（KBD）是一种好发于儿童、严重危害病区居民健康的地方病，目前病因和发病机制仍未完全阐明。Wnt/β-catenin经典信号途径在软骨疾病和骨关节炎的发病中起关键作用，但其是否参与儿童KBD软骨损伤目前尚不清楚，仍有待研究。本项目通过现场流行病学实验和动物实验相结合的方式，从Wnt/β-catenin经典信号途径入手，联系其辅助受体LRP5，一方面观察软骨细胞的凋亡情况，检测凋亡因子和相关凋亡蛋白的水平，分析Wnt/β-catenin经典信号途径对软骨细胞凋亡的影响；另一方面，检测其下游靶基因产物MMP-13、BMP-2和WISP-1的水平，并分析其与软骨代谢产物之间的关系，探讨Wnt/β-catenin经典信号途径对软骨ECM代谢的影响。综合两部分实验结果，探讨儿童KBD关节软骨损伤的具体机制，为进一步阐明KBD的发病机制奠定基础，同时为KBD早期治疗新靶点的确立提供理论依据。

大骨节病（KBD）是一种好发于儿童、严重危害病区居民健康的地方病，目前病因和发病机制仍未完全阐明。本项目通过现场流行病学实验和动物实验相结合的方式，从Wnt/β-catenin经典信号途径入手，联系其辅助受体LRP5，一方面观察软骨细胞的凋亡情况，检测凋亡因子和相关凋亡蛋白的水平，分析Wnt/β-catenin经典信号途径对软骨细胞凋亡的影响；另一方面，检测其下游靶基因产物MMP-13、BMP-2和WISP-1的水平，并分析其与软骨代谢产物之间的关系，探讨Wnt/β-catenin经典信号途径对软骨ECM代谢的影响。本项目人群试验结果显示尿液CTX-Ⅱ和PYD水平可作为儿童大骨节病早期诊断的生物标志物，其中CTX-II的预测精度最高，诊断效力最强。骨端改变儿童大骨节病患者血清β-catenin水平显著高于内对照组和外对照组；病例组儿童血清BMP-2水平显著升高，而WISP-1水平显著降低。而在T-2毒素所致的大鼠关节软骨损伤的模型中，关节深层软骨细胞发生坏死的同时增殖层（中层）细胞过度增殖，但细胞外 II 型胶原的表达并未见明显升高；Wnt/β-catenin信号途径下调（血清学和软骨免疫组化结果联合表明），但其下游靶基因MMP-13和BMP-2的表达增加； 软骨细胞凋亡增加。两部分结果结合在一起，初步说明Wnt/β-catenin信号途径可通过引起软骨细胞异常增殖和过度凋亡，进而参与儿童大骨节病及T-2毒素所致的关节软骨损伤。