人膝骨关节炎胫骨平台关节软骨组织过渡层软骨细胞集落的形成及意义

Formation and significance of chondrocyte cluster in the transitional zone of tibial plateau articular cartilage in human knee osteoarthritis

目的观察膝骨关节炎(OA)患者胫骨平台软骨组织中软骨细胞集落的形成及对膝OA发展的意义。方法根据国际骨关节炎协会(OARSI)人关节软骨组织学等级评定系统获取0~1级、2~3级、4级三组软骨标本,制作组织学切片观察软骨细胞集落形成;免疫组化技术检测集落中软骨细胞Ⅱ型胶原、Ⅹ型胶原、基质金属蛋白酶13(MMP-13)表达情况;获取0~1级、4级两组软骨标本,提取过渡层软骨细胞进行体外培养至第三代,观测24 h增殖率及细胞生长状态。两组间数据比较使用成组t检验。结果OARSI等级0~1级组软骨组织浅表层完整、细胞数量多、过渡层软骨细胞无集落形成,2~3级组软骨组织浅表层破损、细胞数量明显减少、过渡层软骨细胞无集落形成,4级组软骨组织浅表层消失、过渡层出现明显软骨细胞集落;集落中软骨细胞Ⅱ型胶原表达减少,Ⅹ型胶原和MMP-13表达明显增多。体外培养0~1级组过渡层软骨细胞24 h增殖率较4级组低(8%±4%比16%±6%,t=3.722,P=0.002),细胞无明显集落样生长,而4级组软骨细胞呈集落样生长。结论膝OA早期软骨组织浅表层存在时、过渡层软骨细胞增殖率低不形成集落;膝OA中期软骨组织浅表层缺失、过渡层软骨细胞增殖率增高并形成集落,集落中的软骨细胞呈现肥大化改变。

Objective To observe the formation of chondrocyte cluster in tibial plateau articular cartilage in human knee osteoarthritis(OA)and its significance for the development of knee OA.Methods According to Osteoarthritis Research Society International(OARSI)human articular cartilage histological grade system,cartilage samples of grade 0-1,grade 2-3 and grade 4 were obtained and histological sections were made to observe the formation of chondrocyte cluster.Immunohistochemical technique was used to detect the levels of collagenⅡ,collagenⅩand Matrix metalloproteinase-13(MMP-13)in chondrocyte cluster.Cartilage samples of grade 0-1 and grade 4 were obtained,and chondrocytes in transitional zone were extracted for culture to the third generation in vitro,and the proliferation rate and cell growth status at 24 h were observed.The data were compared with group t test between groups.Results The superficial zone of cartilage tissue of grade 0-1 was intact and the number of chondrocytes was abundant,and there was no chondrocyte cluster formation in transitional zone.The superficial zone of chondrocytes in cartilage tissue of grade 2-3 was uneven,the number of chondrocytes decreased obviously,and there was no chondrocyte cluster formation in transitional zone.The superficial zone of chondrocytes in cartilage tissue of grade 4 was absent and there were lots of chondrocyte cluster formation.The level of collagenⅡprotein decreased in chondrocytes in cluster,while the levels of collagenⅩprotein and MMP-13 protein increased.The 24-hour proliferation rate of transitional zone chondrocytes cultured in vitro in grade 0-1 cartilage tissue was lower than that in grade 4(8%±4%vs 16%±6%,t=3.722,P=0.002),and there was no obvious chondrocyte cluster formation in this group.While the chondrocytes from grade 4 cartilage tissue proliferated in the form of cluster.Conclusions The proliferation rate of transitional zone chondrocytes is low and no cluster is formed when the superficial zone exists in the early stage of knee OA.The proliferation rate of transitional zone chondrocytes is higher when the superficial zone is absent,and the chondrocyte cluster formed in the middle stage of knee OA.