Histochemical studies of the extracellular matrix of human articular cartilage - a review

Objective: This paper reviews the histochemistry of the extracellular matrix of human articular cartilage. No systematic review of histochemical knowledge and techniques in the study of articular cartilage has been published previously. Methods and results: Literature was searched in the Winspirs Medline database from 1960 to 2000. Only techniques applicable for bright field or polarization microscopy were considered. Unless otherwise noted, all applies to hyaline cartilage. The most widely used fixatives are adequate for routine staining of proteins, but proteoglycan fixation is problematic, and no one fixative can be recommended. Proteoglycan can be stained reliably but it is problematic that, at low substrate concentrations, these methods are not stoichiometric. Collagen can be stained efficiently, although attempts to differentiate collagen types have not been successful. Conclusions: Detailed studies of fixation and staining procedures should be carried out and standards for cartilage sampling, handling and evaluation agreed upon it results from different laboratories are to be compared. (C) 2002 OsteoArthritis Research Society International. Published by Elsevier Science Ltd. All rights reserved.