Histochemical Localization of Collagen and of Proteoglycans in Tissues
This chapter presents an outline of the most simple and accurate methods that have proved useful for the histochemical study of collagen and proteoglycans. A practical modus operandi, which includes recommended histochemical procedures and interpretation of the results, is presented. Micrographs, tables, and diagrams are provided to summarize the differential procedures. The chapter shows that collagen, proteoglycans, and collagen-proteoglycan interaction, can be demonstrated specifically and quantified in tissue sections with the aid of histochemical reactions. The Picrosirius-polarization method is a specific histochemical procedure for collagen detection in tissue sections and is also useful for studying the differential distribution of the structurally distinct collagen types in routinely fixed, paraffin-embedded organs. Interstitial collagens display different interference colors and intensities of birefringence in tissue sections studied by the Picrosirius-polarization method. Collagen fibers show up in the form of thick, brilliant, yellow or red fibers against a dark background when studied by the Picrosirius-polarization method.