早期骨关节炎模型大鼠半月板白区细胞的超微结构变化

Ultrastructural changes of the white zone cells of the meniscus in a rat model of early osteoarthritis

背景:目前膝骨关节炎的研究重点多在关节软骨、软骨下骨及滑膜,国内外对动物模型半月板超微结构的研究较少。目的:在观察半月板白区软骨细胞超微结构及其类型基础上,观察早期骨关节炎动物模型半月板白区细胞超微结构变化,探讨半月板微观结构变化与生理功能改变的关系。方法:SD大鼠分空白对照组、模型组。模型组通过膝关节腔注射木瓜蛋白酶制作早期骨关节炎动物模型;造模5周后取半月板,电镜制样、定位,观察白区细胞超微结构。实验方案经福建中医药大学动物实验伦理委员会批准。结果与结论:①空白对照组大鼠半月板白区浅表层细胞多呈梭形,里层细胞多呈类三角形,含有丰富的粗面内质网、线粒体,并见高尔基体等细胞器;细胞周围胶原原纤维主要为有序密集的Ⅱ型胶原原纤维;半月板白区细胞为透明软骨细胞。模型组半月板组织表面粗糙;细胞肿胀,粗面内质网等细胞器减少且肿胀变性,糖原蓄积;细胞核多有变形,异染色质凝集;细胞周围胶原原纤维变得杂乱而稀疏;②结果提示,早期骨关节炎半月板软骨细胞与基质轻度退变,将使细胞合成分泌基质成分的能力降低,半月板生理功能将受到影响。

BACKGROUND:The research focuses of knee osteoarthritis are on mainly articular cartilage,subchondral bone and synovium.There are few studies on the ultrastructure of the meniscus in animal models.OBJECTIVE:On the basis of observing the ultrastructure and types of chondrocytes in the white zone of the meniscus,to observe the ultrastructural changes of the white zone cells of the meniscus in an animal model of early osteoarthritis,in order to explore the relationship between the microstructural changes and the physiological functional changes in the meniscus.METHODS:Sprague-Dawley rats were randomly divided into a control group and a model group.Rats in the model group were made into the model of early knee osteoarthritis by intraarticular injection of papain.After 5 weeks,the meniscuses of three rat models in each group were taken,located and observed for the ultrastructure of the white zone cells through a transmission electron microscope.An ethics approval was obtained from the Animal Ethics Committee of Fujian University of Traditional Chinese Medicine.RESULTS AND CONCLUSION:In the control group,most of cells were fusiform in the superficial layer of meniscus and were triangular-like in the deeper layer.They were rich in rough endoplasmic reticulum and mitochondria,with presence of Golgi and other organelles.Extracellular collagen fibrils were mainly type II collagen fibrils.The cells in the white zone of meniscus were chondrocytes.In the model group,the meniscal surface became rough,the cells were swollen,cytoplasmic organelles were reduced and swollen,glycogen was accumulated,and most of nuclei were abnormal with heterochromatin agglutination.Extracellular collagen fibrils became disordered and sparse.These findings indicate that the mild degeneration of chondrocytes and matrix in the meniscus can reduce the ability of cells to synthesize and secrete matrix components,which may lead to the physiological hypofunction.