Studies on Cartilage

Abstract

Electron microscope observations on rabbit ear cartilage following the administration of papain show that both the elastic component of the matrix and the amorphous material disappear leaving a matrix which consists of delicate fibrils which are presumed to be collagen. This unmasking of fibrils coincides with the appearance of an abnormal component in the electrophoretic pattern of the rabbit's serum. The chondrocytes show vacuoles in their cytoplasm which appear at the same time that the cells appear crenated in the light microscope. A ruffly appearance of the cell surface membrane coincides with this vacuolization, and vacuoles often appear open and in continuity with the extracellular space. The resurgence of the rabbit ear is accompanied by a reconstitution of both the amorphous material and the elastic component of the matrix. During this period numerous dilated cisternae of the endoplasmic reticulum which contain a moderately dense material are present in the chondrocyte cytoplasm. We have been unable to demonstrate a direct relationship between the elastic component of the matrix and a particular component of the chondrocyte cytoplasm, but it is clear that changes occur in the cartilage cell cytoplasm during both the depletion and reconstitution of the matrix. Previous studies on the effect of papain on elastic tissue are noted and the possible relationships between changes in the cells and matrix of this elastic cartilage are discussed.The phenomenon of collapse of the ears of young rabbits after papain is administered intravenously was observed by Thomas (1) who reported the reversibility of this phenomenon. He described the appearance of auricular and other cartilage in the light microscope during the phase of collapse, and commented on a loss of basophilia in the cartilage matrix. Further studies on this phenomenon have been reported by Spicer and Bryant (2, 3), McCluskey and Thomas (4), Tsahas (5), and Bryant, Leder, and Stetten (6), who describe the appearance of an abnormal acid component in the electrophoretic pattern of serum after the administration of papain. The present authors thought that this phenomenon of collapse and recovery might prove suitable for an electron microscope

Studies on Ultrastructural Identification and Distribution of Protein-Polysaccharide in Cartilage Matrix

“…The fact that the granules were removed by trypsin indicates that a protein component is also present and that the stability of the complex depends on the integrity of both protein and polysaccharide. It has been demonstrated previously that proteolytic enzymes will destroy the protein-polysaccharide complex in vivo (47,49,51).…”

Recent Trends in the Biochemistry of the Ground Substance of the Connective Tissues

“…Godman July, 1965 cytes, suggesting that the sulphation of the carbohydrate moieties at least occurs in this region of the cell. Subsequently, it is believed that the molecules of the intact complex are conveyed through the cytoplasm to the periphery of the cell in vesicle-like structures and then discharged into the extracellular matrix via stomata in the cell membrane (Godman and Porter, 1960;Sheldon and Robinson, 1960;Godman and Lane, 1964).…”