GODMAN G C, PORTER K R
J Biophys Biochem Cytol. 1960 Dec;8(3):719-60. doi: 10.1083/jcb.8.3.719.
The role of the cells in the fabrication of a connective tissue matrix, and the structural modifications which accompany cytodifferentiation have been investigated in developing epiphyseal cartilage of fetal rat by means of electron microscopy. Differentiation of the prechondral mesenchymal cells to chondroblasts is marked by the acquisition of an extensive endoplasmic reticulum, enlargement and concentration of the Golgi apparatus, the appearance of membrane-bounded cytoplasmic inclusions, and the formation of specialized foci of increased density in the cell cortex. These modifications are related to the secretion of the cartilage matrix. The matrix of young hyaline cartilage consists of groups of relatively short, straight, banded collagen fibrils of 10 to 20 mmicro and a dense granular component embedded in an amorphous ground substance of moderate electron density. It is postulated that the first phase of fibrillogenesis takes place at the cell cortex in dense bands or striae within the ectoplasm subjacent to the cell membrane. These can be resolved into sheaves of "primary" fibrils of about 7 to 10 mmicro. They are supposedly shed (by excortication) into the matrix space between the separating chondroblasts, where they may serve as "cores" of the definitive matrix fibrils. The diameter of the fibrils may subsequently increase up to threefold, presumably by incorporation of "soluble" or tropocollagen units from the ground substance. The chondroblast also discharges into the matrix the electrondense amorphous or granular contents of vesicles derived from the Golgi apparatus, and the mixed contents of large vacuoles or blebs bounded by distinctive double membranes. Small vesicles with amorphous homogeneous contents of moderate density are expelled in toto from the chondroblasts. In their subsequent evolution to chondrocytes, both nucleus and cytoplasm of the chondroblasts undergo striking condensation. Those moving toward the osteogenic plate accumulate increasingly large stores of glycogen. In the chondrocyte, the enlarged fused Golgi vesicles with dense contents, massed in the juxtanuclear zone, are the most prominent feature of the cytoplasm. Many of these make their way to the surface to discharge their contents. The hypertrophied chondrocytes of the epiphyseal plate ultimately yield up their entire contents to the matrix.
利用电子显微镜，对胎鼠生长板软骨中细胞在结缔组织基质形成中的作用以及伴随细胞分化的结构变化进行了研究。软骨前间充质细胞向成软骨细胞的分化表现为内质网广泛形成、高尔基体增大并集中、出现膜结合的胞质内含物以及在细胞皮质中形成密度增加的特殊区域。这些变化与软骨基质的分泌有关。年轻透明软骨的基质由10至20微米的相对短、直、带状胶原纤维束以及嵌入中等电子密度无定形基质中的致密颗粒成分组成。据推测，原纤维形成的第一阶段发生在细胞膜下方外质中的致密带或条纹处的细胞皮质。这些可分解为约7至10微米的“初级”纤维束。它们可能（通过外皮剥脱）脱落到分离的成软骨细胞之间的基质空间中，在那里它们可作为最终基质纤维的“核心”。纤维直径随后可能增加至三倍，推测是通过从基质中掺入“可溶性”或原胶原蛋白单位。成软骨细胞还将源自高尔基体的小泡的电子致密无定形或颗粒内容物以及由独特双膜界定的大液泡或泡的混合内容物排放到基质中。具有中等密度无定形均匀内容物的小泡从成软骨细胞中整体排出。在它们随后向软骨细胞的演化过程中，成软骨细胞的细胞核和细胞质都经历显著浓缩。那些向成骨板移动的细胞积累了越来越多的糖原储备。在软骨细胞中，具有致密内容物的增大融合高尔基体小泡聚集在核周区域，是细胞质最突出的特征。其中许多小泡到达表面以排出其内容物。生长板肥大的软骨细胞最终将其全部内容物释放到基质中。
