Hirano H, Urist M R
Clin Orthop Relat Res. 1981 Jan-Feb(154):234-48.
The differentiation of connective tissue outgrowths of adult bone marrow in response to the organic matrix of bone was observed in tissue culture by correlated histologic, electron microscopic, biochemical, and radioisotope-labeling methods. On a substratum of bone matrix gelatin, myelogenous cells degenerate and disappear while stromal and perivascular cells proliferate and differentiate into mesenchymal-type, monocytoid, and giant cells. From primary cultures of bone marrow cells on bone matrix, cartilage differentiates in isolated areas but only in small islets. With continuous subculture through 25 generations, the proportions of two functionally different populations of chondrogenetic and matrix-resorbing cells gradually emerge. Up to the time of the ninth generation of subculture, the chondrogenetic population predominates. After the 14th to the 25th generation, clones of matrix-resorbing large monocytoid cells predominate and rapidly digest the matrix substratum. Measurements of 35S uptake demonstrate that control cultures of muscle-derived mesenchymal-type cells produce about twice as much cartilage as marrow-derived mesenchymal-type cells. A decline in the chondrogenetic cell population and corresponding rise in the matrix-resorbing cell population is demonstrable by a progressive increase in the quantity of hydroxyproline-containing peptides in the culture medium. This decline is not attributable to conditions in culture because there was progressive loss of chondrogenetic activity of the eighth and 20th passage even when the cells were transplanted in diffusion chambers back into an isologous host. The problem is how to account for the competence of marrow stromal cells to differentiate into bone without bone matrix in vivo but not in vitro. Mixed cultures of muscle and marrow outgrowths produce only half as much cartilage (measured by 36S-uptake/microgramDNA in the system) as muscle outgrowths alone. These observations suggest that a bone marrow-derived matrix-resorbing cell population, by some unknown mechanism, inhibits proliferation of cartilage-bone precursor cell populations. The nature of the inhibition requires investigation by detailed biochemical analyses of marrow cell culture media and chemical extracts of whole bone marrow tissue.
通过相关的组织学、电子显微镜、生化和放射性同位素标记方法，在组织培养中观察了成年骨髓结缔组织生长物对骨有机基质的反应。在骨基质明胶基质上，骨髓细胞退化并消失，而基质细胞和血管周围细胞增殖并分化为间充质型、单核细胞样和巨细胞。从骨髓细胞在骨基质上的原代培养物中，软骨在孤立区域分化，但仅在小胰岛中分化。经过25代连续传代培养，两种功能不同的软骨生成细胞群和基质吸收细胞群的比例逐渐显现。直到传代培养的第九代，软骨生成细胞群占主导地位。在第14代到第25代之后，基质吸收性大单核细胞样细胞克隆占主导地位，并迅速消化基质底物。对35S摄取的测量表明，肌肉来源的间充质型细胞的对照培养物产生的软骨约为骨髓来源的间充质型细胞的两倍。培养基中含羟脯氨酸肽的量逐渐增加，表明软骨生成细胞群减少，基质吸收细胞群相应增加。这种减少并非归因于培养条件，因为即使将细胞移植到扩散室中并回植到同基因宿主中，第8代和第20代传代的软骨生成活性仍在逐渐丧失。问题在于如何解释骨髓基质细胞在体内而非体外无骨基质的情况下分化为骨的能力。肌肉和骨髓生长物的混合培养物产生的软骨（通过系统中36S摄取/微克DNA测量）仅为单独肌肉生长物的一半。这些观察结果表明，骨髓来源的基质吸收细胞群通过某种未知机制抑制软骨-骨前体细胞群的增殖。这种抑制的性质需要通过对骨髓细胞培养基和全骨髓组织化学提取物进行详细的生化分析来研究。
