Visualization of sulfur-containing components associated with proliferating chondrocytes from rat epiphyseal growth plate cartilage: Possible proteoglycan and collagen co-migration

1990 ◽  
Vol 226 (2) ◽  
pp. 153-167 ◽  
Author(s):  
William J. Landis ◽  
Karen J. Hodgens
Keyword(s):  
Growth Plate ◽  
Epiphyseal Growth Plate ◽  
Growth Plate Cartilage ◽  
Sulfur Containing

scholarly journals Ultrastructural analysis of cytochrome oxidase in chick epiphyseal growth plate cartilage.

1988 ◽  
Vol 36 (9) ◽  
pp. 1161-1166 ◽  
Author(s):  
T Yamamoto ◽  
C V Gay
Keyword(s):  
Cytochrome Oxidase ◽  
Growth Plate ◽  
Oxidative Metabolism ◽  
Anaerobic Metabolism ◽  
Epiphyseal Growth Plate ◽  
Growth Plate Cartilage ◽  
Proliferative Zone ◽  
Relationship Of ◽  
The Relationship ◽  
Aerobic And Anaerobic

Histochemical detection of cytochrome oxidase activity in chicken growth plate revealed both positively and negatively stained mitochondria in chondrocytes of all zones, i.e., proliferative, pre-hypertrophic, hypertrophic, and calcifying zones. The proportion of positive to negative cells was lowest in the proliferative zone. As cytodifferentiation progressed, more positively stained cells were present. In positive cells all mitochondria were usually stained, and in negative cells all mitochondria were unstained. A few cells appeared to be in transition and contained both types of mitochondria. The results indicate that chondrocytes utilizing both aerobic and anaerobic metabolism are present in growth plate cartilage and that oxidative metabolism is favored in the more mature cells. The relationship of oxidative metabolism to calcification is discussed.

scholarly journals Locally produced estrogen promotes fetal rat metatarsal bone growth; an effect mediated through increased chondrocyte proliferation and decreased apoptosis

2006 ◽  
Vol 188 (2) ◽  
pp. 193-203 ◽  
Author(s):  
A S Chagin ◽  
D Chrysis ◽  
M Takigawa ◽  
E M Ritzen ◽  
L Sävendahl
Keyword(s):  
Growth Plate ◽  
Bone Growth ◽  
Longitudinal Growth ◽  
Epiphyseal Growth Plate ◽  
Chondrocyte Proliferation ◽  
Growth Plate Cartilage ◽  
Ici 182,780 ◽  
Metatarsal Bones ◽  
Fetal Rat ◽  
Estrogen Synthesis

The importance of estrogens for the regulation of longitudinal bone growth is unequivocal. However, any local effect of estrogens in growth plate cartilage has been debated. Recently, several enzymes essential for estrogen synthesis were shown to be expressed in rat growth plate chondrocytes. Local production of 17β-estradiol (E2) has also been demonstrated in rat costal chondrocytes. We aimed to determine the functional role of locally produced estrogen in growth plate cartilage. The human chondrocyte-like cell line HCS-2/8 was used to study estrogen effects on cell proliferation (3H-labeled thymidine uptake) and apoptosis (cell death detection ELISA kit). Chondrocyte production of E2 was measured by RIA and organ cultures of fetal rat metatarsal bones were used to study the effects of estrogen on longitudinal growth rate. We found that significant amounts of E2 were produced by HCS-2/8 chondrocytes (64.1 ± 5.3 fmol/3 days/106cells). The aromatase inhibitor letrozole (1 μM) and the pure estrogen receptor antagonist ICI 182,780 (10 μM) inhibited proliferation of HCS-2/8 chondrocytes by 20% (P<0.01) and almost 50% (P<0.001), respectively. Treatment with ICI 182,780 (10 μM) increased apoptosis by 228% (P<0.05). Co-treatment with either caspase-3 or pan-caspase inhibitors completely blocked ICI 182,780-induced apoptosis (P<0.001 vs ICI 182,780 only). Moreover, both ICI 182,780 (10 μM) and letrozole (1 μM) decreased longitudinal growth of fetal rat metatarsal bones after 7 days of culture (P<0.01). In conclusion, our data clearly show that chondrocytes endogenously produce E2 and that locally produced estrogen stimulates chondrocyte proliferation and protects from spontaneous apoptosis. In addition, longitudinal growth is promoted by estrogens locally produced within the epiphyseal growth plate.

scholarly journals Ultrastructural localization of calcium-activated adenosine triphosphatase (Ca2+-ATPase) in growth-plate cartilage.

1985 ◽  
Vol 33 (9) ◽  
pp. 925-932 ◽  
Author(s):  
T Akisaka ◽  
C V Gay
Keyword(s):  
Plasma Membrane ◽  
Enzymatic Activity ◽  
Growth Plate ◽  
Golgi Complex ◽  
Adenosine Triphosphatase ◽  
Matrix Vesicles ◽  
Matrix Vesicle ◽  
Epiphyseal Growth Plate ◽  
Growth Plate Cartilage ◽  
Vesicle Membranes

The electron-microscopic cytochemical localization of calcium-activated adenosine triphosphatase (Ca2+-ATPase) was determined in chick epiphyseal growth-plate cartilage. In the reserve zone, mitochondria and lysosomes contained substantial amounts of reaction product, while the plasma membrane and the Golgi complex showed very weak enzymatic activity, and matrix vesicle membranes did not exhibit the cytochemical reaction. As maturation proceeded, the plasma membrane, Golgi complex, and matrix vesicle membranes also stained and were most intense in the proliferative and early hypertrophic zones. From the hypertrophic to the calcifying zone, cytochemical staining decreased progressively in the plasma membrane, the Golgi complex, and lysosomes, while in some cases mitochondrial reaction product remained intense. Matrix vesicles lost their enzymatic activity at the same time that matrix vesicle calcification commenced. It is proposed that this event allows matrix vesicles to calcify, since efflux of calcium would no longer occur.

scholarly journals Ultrastructural demonstration of increased sulfated proteoglycans and calcium associated with chondrocyte cytoplasmic processes and matrix vesicles in rat growth plate cartilage.

1989 ◽  
Vol 37 (7) ◽  
pp. 1025-1033 ◽  
Author(s):  
M Takagi ◽  
T Sasaki ◽  
A Kagami ◽  
K Komiyama
Keyword(s):  
Growth Plate ◽  
Close Association ◽  
Freeze Substitution ◽  
Matrix Vesicles ◽  
Immunoperoxidase Staining ◽  
Cytoplasmic Process ◽  
Epiphyseal Growth Plate ◽  
Growth Plate Cartilage ◽  
Cytoplasmic Processes ◽  
Sulfated Proteoglycans

A monoclonal antibody (3-B-3) to chondroitin 6-sulfated proteoglycan was used with immunoperoxidase electron microscopy to study the relationship of chondrocyte cytoplasmic processes and matrix vesicles in rat epiphyseal growth plate cartilage. Immunoperoxidase staining of the chondrocyte plasmalemma was found at all levels in the growth plate and was most prominent in the hypertrophic zone. The plasmalemma and matrix of the cytoplasmic process often demonstrated stronger reactivity than the remainder of the cell surface. Matrix vesicles showed weak to strong surface or internal reactivity. The majority of them stained very similarly to the cytoplasmic process. X-ray microanalysis of specimens processed by rapid freezing and freeze substitution confirmed that both sulfur and calcium were localized within or in close association with both the cytoplasmic process and the matrix vesicle, suggesting a chemical combination of calcium with sulfated proteoglycans at both sites. These results indicate that there is a selective increase in the concentration of membrane-associated sulfated proteoglycan and calcium in the cell process, from which matrix vesicles may be released into the extracellular matrix.

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