ABSTRACT
This chapter shows that how Electron microscopy (EM) and polarization microscopy (PM) can complement each other in ultrastructure research of the glycosarninoglycan and proteoglycan (PG) molecules in the extracellular matrix (ECM) of the cartilage tissue. EM and PM techniques reveal ultra-structural patterns in different ways. While EM directly visualizes the structures, PM is an indirect method that is the ultrastructure can be inferred from the optical phenomena observed or measured in the microscope. The structures are differently altered during the different preparative methods of the specimens used in these two techniques, that is different artifacts are formed, observed, and compared. The minute section thickness and high magnification used in the transmission EM to image details of the ECM limits the analysis to a very restricted field. The cationic dyes used in electron microscopic histochemistry of PGs can be divided into the following two categories: dyes without electron-dense atoms and metal-containing dyes.
