Abstract:

BACKGROUND: Chondron is a basic microanatomical unit of articular cartilage. Increasing evidence suggests that the pericellular matrix (PCM) is a distinct functional compartment in articular cartilage, influencing the metabolic, micromechanical environment, and degeneration of chondrocytes. But the precise functions and action mechanism need further investigation.
OBJECTIVE: To review the literature pertinent to the morphology, function, isolation of the chondron in articular cartilage, and its degenerative events during the progression of osteoarthritis (OA).
METHODS: This review summarized the articles published in the PubMed database before July 2009. In addition, recent data and figure of our laboratory on the morphology and biomechanics of chondron and chondrocyte were supplemented.
RESULTS AND CONCLUSION: The PCM is primarily characterized by the presence of type Ⅵ collagen, and these components are widespread in the expansive extracellular matrix (ECM) in newborns, while in mature the components are mainly localized to a narrow pericellular zone. The three-dimensional morphology of chondron has been recently quantified in situ with fluorescence confocal microscopy, and the mechanical properties of the isolated individual chondrons and their PCM are measured using the micropipette technique and atomic force microscopy. More studies have shown that the presence of the PCM in chondrons has a profound influence on chondrocyte gene expression. At the same time, structural, histochemical and biomechanical studies indicate the chondron and their PCM may undergo degenerative processes with osteoarthritis, similar to those occurring in the ECM. Although the precise function of the PCM is unknown, increasing evidence in vivo or in vitro suggests that the PCM is a basic microanatomical unit in articular cartilage, influencing the metabolic and micromechanical environment of chondrocytes.