Light and electron microscopic morphology of the temporomandibular joint in growing and mature crab-eating monkeys (Macaca fascicularis): the condylar calcified cartilage

Abstract

In an attempt to show maturational alterations in the calcified cartilage, mandibular condyles of four growing and four adult male monkeys (Macaca fascicularis) were studied using light microscopy as well as transmission and scanning electron microscopy. All specimens were initially fixed by perfusion in the presence of ruthenium red. For examination of the hard tissue surfaces in the scanning electron microscope, uncalcified tissues were removed with sodium hypochlorite. In growing animals, almost the entire hard tissue surface in the joint region of the condyle was formed by calcified cartilage, while in adult animals, calcified cartilage was confined to load-bearing regions. In growing animals, the appearance of the calcified cartilage surface suggested a continuously advancing mineralizing front similar to that seen in the epiphyseal plate. Chondrocytes mostly exhibited a terminal stage of hypertrophy, and seemed to die and get lost through vascular invasion and subsequent endochondral ossification. In adult animals, most of the calcified cartilage surface appeared comparatively stable, and resembled the tidemark of articular cartilage. Chondrocytes were usually small and appeared viable. However, on the adult condyles, there were always circumscribed islands where chondrocytes and the pattern of mineralization resembled those seen in growing animals. In these regions, prominent chondroclastic activity indicated extensive articular remodelling. These observations suggest that at the end of somatic growth, condylar calcified cartilage undergoes considerable maturation from a type reminiscent of hyaline growth cartilage to a type resembling articular cartilage. Concomitantly, chondrocytes appear to change their developmental program, in that they stop enlarging and lose their commitment to death. However, they may be able to retain, or switch back to, a more immature stage, in case there is need for extensive articular remodelling.

Calcified cartilage zone and its dimensional relationship to the articular cartilage in the human temporomandibular joint of elderly individuals

“…Therefore, it might be suspected that the presence of blood vessels in the CCZ of human TMJ is a marker of an ongoing process such as in degenerative joint disease or remodeling. Such a theory has also been proposed by Moffett et al (22) and more recently by Luder & Schroeder (28), who in an ultrastructural study on TMJs from Mucuca monkeys found that vascular canals penetrating the osteochondral junction were related to chondroclast resorption and articular remodeling.…”

Localization of types I, II and X collagen and osteocalcin in intramembranous, endochondral and chondroid bone of rats

“…(Enlow 1962;Hall 1972;Beresford 1981;Hinton and Carlson 1983;Goret-Nicaise 1984;Silbermann et al 1987a;Luder and Schroeder 1992;Ben-Ami et al 1993;Mizoguchi et al 1993;Sasano et al 1993;Taylor et al 1994;Lengele et al 1996). As revealed by immunohistochemistry, chondroid bone contains both types I and II collagen, which are ECM components of bone and cartilage, respectively (Enlow 1962;Goret-Nicaise 1984;Silbermann et al 1987b;Ben-Ami et al 1993;Mizoguchi et al 1993;Sasano et al 1993).…”

“…As revealed by immunohistochemistry, chondroid bone contains both types I and II collagen, which are ECM components of bone and cartilage, respectively (Enlow 1962;Goret-Nicaise 1984;Silbermann et al 1987b;Ben-Ami et al 1993;Mizoguchi et al 1993;Sasano et al 1993). It has been suggested as a possibility that chondrocytes may transdifferentiate into the osteogenic lineage in chondroid bone (Enlow 1962;Hall 1972;Luder and Schroeder 1992). However, little information is available concerning the exact composition of chondroid bone, especially the ECMs associated with matrix calcification.…”

Expression of osteogenic proteins during the intrasplenic transplantation of Meckel's chondrocytes: A histochemical and immunohistochemical study

“…This tissue develops as an intermediate tissue of cartilage and bone: the cells are larger than osteogenic cells and express some chondrogenic markers such as type II collagen, but its extracellular matrix appears bone-like by staining for proteoglycans (Lengelé et al, 1996). Some investigators including Enlow (1962), Hall (1972), and Luder and Schroeder (1992) have suggested the possibility that the cells in the chondroid bone transdifferentiate into osteogenic cells. Mizoguchi et al (1997) detected the expression of types I, II, and X collagen as well as osteocalcin in the chondroid bone matrix of rat glenoid fossa using immunocytochemistry, and reported that, since neither the active deposition of a bone matrix nor intracellular labeling for osteocalcin were observed, the cells within the chondroid bone apparently displayed osteocytic, rather than osteoblastic, characteristics.…”