ABSTRACT
Polarization-microscopic investigations revealed a predominantly axioparallel orientation of glycosaminoglycans (GAGs) and collagen in extracellular matrix (ECM) of different connective tissues. These data suggest that interactions between GAGs and collagen fibrils may be responsible for the oriented deposition of GAGs in the extra celluar space. Electron-microscopic investigations revealed a predominantly axiperpendicular orientation of the proteoglycan (PG) molecules to collagen fibrils in ECM of soft connective tissues such as tendons, skin, sclera, and cornea. A similar orientation pattern of one population of cartilage PGs has been demonstrated electronmicroscopically. The binding of different polyanions to the tissue could be detected by metachromatic dyes. The binding of polyanions did not show any tissue specifity. Besides cartilage matrix, the cytoplasm of different cells and other structures including skeletal muscle, perichondrium, and vessel walls, became metachromatic. Polarization microscopic analysis of the digested, incubated and stained sections reveals optical anisotropy in collagen-containing structures.
