TY - JOUR
T1 - Meckel's cartilage chondrocytes in organ culture synthesize bone-type proteins accompanying osteocytic phenotype expression
AU - Ishizeki, Kiyoto
AU - Takigawa, Masaharu
AU - Harada, Yorio
AU - Suzuki, Fujio
AU - Nawa, Tokio
PY - 1996
Y1 - 1996
N2 - We examined whether Meckel's cartilage of embryonic mice, 17 days in utero, undergo the cellular transformation into the osteocyte-like phenotype under organ culture conditions. Explants were grown by our original pithole method modified Trowell-type cultures for up to 4 weeks at 37°C under 5% CO2 in air. Specimens were examined using histological procedures including immunostaining and electron microscopy. In addition, the effects of β-glycerophosphate on matrix calcification were also examined in cultures with or without β-glycerophosphate. Addition of β-glycerophosphate induced calcification at a higher level, but calcium mineral deposition occurred regardless of the addition of β-glycerophosphate to the culture medium. Light and electron microscopic analyses showed that freshly isolated chondrocytes prior to cell culture had typical hypertrophic morphology, but shortly after commencement of culture, they showed morphological modifications. The cells showing chondrocytic phenotypes became basophilic elliptical cells, and eventually transformed into flattened osteocyte-like cells. Bone-like features for cellular elements were characterized by spindle-shaped cells with elongated processes accompanying bone-specific thick-banded collagen fibrils. Immunostaining showed that at 2 weeks in culture, type I and type II collagens coexisted in the matrix, but subsequently type II collagen synthesis ceased and was replaced by type I collagen synthesis. Immunofluorescent labeling for osteocalcin was noted first in the peripheral cells by 1 week, but at 3 weeks this reaction spread to the central zone in explants. Alkaline phosphatase activity (ALPase) was expressed on the cells in the central zone prior to calcium mineral deposition as shown by von Kossa's reaction at 3 weeks in culture. These results showed that Meckel's cartilage chondrocytes in organ culture synthesize bone-type proteins accompanying osteocytic phenotype expression.
AB - We examined whether Meckel's cartilage of embryonic mice, 17 days in utero, undergo the cellular transformation into the osteocyte-like phenotype under organ culture conditions. Explants were grown by our original pithole method modified Trowell-type cultures for up to 4 weeks at 37°C under 5% CO2 in air. Specimens were examined using histological procedures including immunostaining and electron microscopy. In addition, the effects of β-glycerophosphate on matrix calcification were also examined in cultures with or without β-glycerophosphate. Addition of β-glycerophosphate induced calcification at a higher level, but calcium mineral deposition occurred regardless of the addition of β-glycerophosphate to the culture medium. Light and electron microscopic analyses showed that freshly isolated chondrocytes prior to cell culture had typical hypertrophic morphology, but shortly after commencement of culture, they showed morphological modifications. The cells showing chondrocytic phenotypes became basophilic elliptical cells, and eventually transformed into flattened osteocyte-like cells. Bone-like features for cellular elements were characterized by spindle-shaped cells with elongated processes accompanying bone-specific thick-banded collagen fibrils. Immunostaining showed that at 2 weeks in culture, type I and type II collagens coexisted in the matrix, but subsequently type II collagen synthesis ceased and was replaced by type I collagen synthesis. Immunofluorescent labeling for osteocalcin was noted first in the peripheral cells by 1 week, but at 3 weeks this reaction spread to the central zone in explants. Alkaline phosphatase activity (ALPase) was expressed on the cells in the central zone prior to calcium mineral deposition as shown by von Kossa's reaction at 3 weeks in culture. These results showed that Meckel's cartilage chondrocytes in organ culture synthesize bone-type proteins accompanying osteocytic phenotype expression.
KW - Calcification
KW - Meckel's cartilage
KW - Organ culture
KW - Osteocyte-like cell
KW - Transformation
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U2 - 10.1007/BF00186834
DO - 10.1007/BF00186834
M3 - Article
C2 - 8838497
AN - SCOPUS:0030042749
VL - 193
SP - 61
EP - 71
JO - Anatomy and Embryology
JF - Anatomy and Embryology
SN - 0340-2061
IS - 1
ER -