Human Health Sciences, Graduate School of Medicine, Kyoto University, Japan.
Osteoarthritis Cartilage. 2013 Aug;21(8):1092-8. doi: 10.1016/j.joca.2013.04.021. Epub 2013 May 13.
Articular cartilage is roughly separated into three areas: the tangential, middle, and deep zones. The structure and molecular components of an additional important zone, the most superficial zone (MSZ), which directly faces the joint cavity, have yet to be conclusively elucidated. The purpose of the present study was to use multiple methods to study the MSZ in order to determine its structure.
Knees from 16 pigs (age, 6 months) were used. Full-thickness cartilage specimens were harvested from the femoral groove. The MSZ was observed using light microscopy, transmission electron microscopy (TEM), and scanning electron microscopy (SEM) in combination with histochemical and immunohistochemical methods.
The combined findings from the three different observational methods indicate that the MSZ is subdivided into three layers. Among these three layers, collagen subtypes I, II, and III are present in the innermost (third) layer of the MSZ. Beneath the third layer, type II collagen is the predominant type, with small amounts of type III collagen. This layer beneath the third layer is considered to be the tangential layer.
Our observations indicate that the MSZ is subdivided into three layers. Further analysis of the molecular components in each layer may improve our understanding of the structure of the articular surface.
关节软骨大致可分为三个区域：切线区、中间区和深层区。一个额外的重要区域，即最表层区（MSZ）的结构和分子成分尚未得到明确阐明，该区域直接面对关节腔。本研究旨在采用多种方法研究 MSZ 以确定其结构。
使用 16 只 6 月龄猪的膝关节。从股骨沟中采集全层软骨标本。采用光镜、透射电镜（TEM）和扫描电镜（SEM）结合组织化学和免疫组织化学方法观察 MSZ。
三种不同观察方法的综合结果表明，MSZ 分为三层。在这三层中，MSZ 的最内层（第三层）存在 I 型、II 型和 III 型胶原。在第三层下方，II 型胶原是主要类型，少量存在 III 型胶原。这一层被认为是切线层。
我们的观察表明 MSZ 分为三层。进一步分析各层的分子成分可能有助于我们了解关节表面的结构。
