Correlation of freeze-fracture and scanning electron microscopy of epiphyseal chondrocytes
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Chondrocytes in epiphyseal cartilage were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) using freeze-fracture techniques. Freeze-fracture replicas showed large numbers of fingerlike, 0.11–0.15 μm diameter, projections from the chondrocyte surface, with numerous 95–180 Å diameter intramembranous particles associated with both the cell membrane surface and these projections. With SEM, these cytoplasmic projections were also obvious, but appeared collapsed into clusters of globular-shaped projections on the surface of the chondrocytes. With freeze-fracture techniques, in which shrinkage artifacts were essentially eliminated, the cytoplasmic projections were often seen in intimate contact with the extracapsular matrix. However, with chondrocytes prepared by both SEM and conventional TEM, there was evidence of shrinkage, the cytoplasmic projections having little contact with the extracapsular matrix. These findings show that the cytoplasmic processes are not artifacts of tissue processing and provide morphological evidence in support of the hypothesis that matrix vesicles are of cellular origin.
Key wordsEpiphyseal chondrocytes Freezefracture Scanning electron microscopy Cell processes Membrane particles
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- 4.Zimny, M.L., Redler, I.: Scanning electron microscopy of chondrocytes, Acta Anat. (Basel)83:398–402, 1972Google Scholar
- 5.Lufti, A.M.: The ultrastructure of cartilage cells in the epiphyseal plate of long bones in the domestic fowl, Acta Anta. (Basel)87:12–21, 1974Google Scholar
- 7.Savostin-Asling, I., Asling, C.E.: Transmission and scanning electron microscope studies of calcified cartilage resorption. Anat. Rec.,193:373–391, 1975Google Scholar
- 10.Spycher, M.A., Moor, H., Ruettner, J.E.: Electron microscopic investigations on ageing and osteoarthrotic human articular cartilage. II. The fine structures of freeze-etched ageing hip joint cartilage, Z. Zellforsch. Microsk. Anat.98:512–524, 1969Google Scholar