Ultrastructural distribution of sulfated complex carbohydrates in elastic cartilage of the young rabbit

Abstract

Sulfated glycosaminoglycans are an integral component of elastic cartilage. We have investigated the ultrastructural distribution of sulfated complex carbohydrates (CC) in the mature cartilage and the perichondrium of young rabbit auricles using the high iron diamine-thiocarbohydrazide-silver proteinate (HID-TCH-SP) and the tannic acid-ferric chloride (TA-Fe) methods. In the mature cartilage, HID-TCH-SP stained intracellular Golgi saccules of the mature face, secretory granules, and the extracellular matrix granules, but staining was not discernible in collagen fibrils and osmiophilic elastic fibers consisting of only amorphous elastin. The HID and TA-Fe staining were similarly observed in matrix granules, whereas the elastic fibers and collagen fibrils lacked the staining. The pericellular matrix granules had a diameter of 34 +/- 5 nm (mean +/- SD; n = 30). Thiéry's periodate-TCH-SP (PA-TCH-SP) method stained vicinal glycol-containing CC in collagen fibrils but failed to stain matrix granules and elastic fibers. In the perichondrium, HID-TCH-SP staining of the organelles was less intense in the flattened chondrocytes when compared with those in large mature chondrocytes. The extracellular HID and HID-TCH-SP staining were observed in the matrix granules. The diameter of pericellular matrix granules (19 +/- 4 nm, mean +/- SD; n = 30) was significantly smaller when compared to those in the mature cartilage (P less than 0.001). The HID-TCH-SP staining was closely associated with collagen fibrils. However, the staining was not seen in collagen fibrils and osmiophilic elastic fibers consisting of elastin and microfibrils. The PA-TCH-SP method stained collagen fibrils and microfibrils but did not stain the amorphous elastin. Thus these studies demonstrate that sulfated CC are packaged in chondrocyte secretory granules and are released into the extracellular matrix to form matrix granules, but are not incorporated into collagen fibrils and elastic fibers.

Ultrastructural cytochemistry of carbohydrates in microfibrils associated with the amorphous elastin in the monkey aorta

“…The demonstration of PA-TCH-SP, Con A, and WGA-positive carbohydrates in microfibrils is consistent with biochemical studies demonstrating the presence of PA Schiff (PAS)-reactive material (Muir et al, 1976;Cleary et al, 1981;Sear et al, 1981;Serafini-Fracassini et al, 1981) and a number of sugar moieties including hexose and hexosamine (Ross and Bornstein 1970) in the isolated microfibril component from elastic tissues. Furthermore, this observation is in agreement with previous ultrastructural studies using PA-TCH-SP to localize vicinal glycols in microfibrils of rabbit elastic cartilage perichondrium (Takagi et al, 1983) and the rat aorta (Takagi et al, 1984). Immunocytochemical studies examining the localization of endogenous mammalian lectin in lung elastic fibers have suggested reactivity of a 0-galactoside-binding lectin with the microfibrillar glycoproteins (Cerra et al, 1984) comparable to that we have observed with the Con A staining method.…”

“…Other biochemical andlor immunologic studies have also correlated a glycoprotein with the morphological entity termed the microfibril (Muir et al, 1976;Kewley et al, 1977;Sear et al, 1978Sear et al, , 1981Cleary et al, 1981;Serafini-Fracassini et al, 1981). Previous ultrastructural cytochemical studies, using Thiery's (1967) periodic acidthiocarbohydrazide-silver proteinate (PA-TCH-SP) method, analogous to the PA-Schiff (PAS) method, have localized vicinal-glycol-containing complex carbohydrates closely associated with microfibrils in rabbit elastic cartilage perichondrium (Takagi et al, 1983) and rat aorta (Takagi et al, 1984). Birembaut et al (1982) have…”

Ultrastructural cytochemistry of oxytalan fibers in the periodontal ligament and microfibrils in the aorta with the periodic acid‐thiocarbohydrazide‐silver proteinate method

“…Thiery's (11) periodic acid-thiocarbohydrazide-silver proteinate (PA-TCH-SP) method, specific for vicinal glycol-containing complex carbohydrates, has been employed to distinguish tbe PA-TCH-SP reactive microfibrils from the unreactive amorphous clastin in the elastic cartilage and the perichondrium of rabbit auricles (12). However, this method has not been utilized in studies of oxytalan fibers in the periodontal ligaments and inicrofibrils, presumed to be oxytalan libers (10), in aortic tunica adventitia.…”

Increased mesenchymal cell density accompanies induction of tropoelastin expression in developing elastic tissue

“…Bar = 40 pm. Bradamante and Svajger, 1977;Cox and Peacock, 1977;Kostovic-Knezevic et al, 1981Takagi et al, 1983). The most peripheral is the perichondrium, which is comprised of fibroblasts and a type I collagenrich matrix.…”

“…Chondrocytes increase in size manyfold through development, so that in mature cartilage the space occupied by cells is relatively large and, consequently, the intervening matrix is sparse. Microfibrils are seen in the prechondrogenic core before insoluble elastin is deposited but in mature tissue remain visible only in the perichondrial areas (Bradamante et al, 1975;Bradamante and Svajger, 1977;Cox and Peacock, 1977;Kostovic-Knezevic et al, 1981Takagi et al, 1983).…”