Electron Microscopic Studies of Cartilage Matrix Using Lysozyme as a Vital Stain

During the course of a series of studies which had as their aim the elucidation of the role of lysozyme in cartilage metabolism (1-4), it was found that, when egg white lysozyme (LYS) was added to organ cultures of ossifying cartilage (cartilage which contains an epiphyseal growth plate) but not nonossifying cartilage (cartilage which does not contain a growth plate), the lysozyme bound to cartilage matrix in specific anatomic sites. In recent years a number of techniques, including staining with lanthanum and bismuth salts (5, 6), ruthenium red (7), and colloidal iron (8), as well as the addition of cetylpyridinium chloride to fixatives (9), have been used for the visualization of mucopolysaccharides for electron microscopy. The rationale of most of these methods, where they are not completely empirical, in-