Fractal geometry in rat chimeras demonstrates that a repetitive cell division program may generate liver parenchyma.
Fractal geometry in rat chimeras demonstrates that a repetitive cell division program may generate liver parenchyma.
复制标题
大鼠嵌合体的分形几何表明，重复的细胞分裂程序可能会产生肝实质。
DOI：
10.1006/dbio.1994.1274
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发表时间：
1994
影响因子：
2.7
通讯作者：
Iannaccone,PM
中科院分区：
文献类型：
--
作者：
Khokha,MK;Landini,G;Iannaccone,PM
在哺乳动物器官的发育过程中，器官原基分配后，实质区室必须发生快速而有力的扩张。必须调节这种扩张，以便产生足够的组织块以进一步组织成功能组织。大鼠嵌合体肝脏中的镶嵌斑块是分形的（一种具有特征复杂性的几何形式）这一发现表明了一种可能的薄壁组织生成程序的信息存储方案。由于分形物体是通过重复应用特定规则而产生的，因此这种机制可能负责器官实质的生成。这里考虑的用于生成器官实质的模型细胞分裂程序是随机选择一个细胞进行分裂并将子细胞放置在随机选择的相邻位置，取代可能占据所选位置的其他细胞。分裂完成后会创建一个新的细胞群，代表下一次分裂的输入条件。当在包含两个遗传上可区分的细胞群的组织中一遍又一遍地重复这一过程时，对所获得的镶嵌图案的几何形状的分析应该满足特定的预测。如果细胞分裂以这种方式发生，则斑块边界的复杂性（斑块是嵌合体组织中相同标记谱系的细胞的连续聚集体）应该独立于构成嵌合体组织的两个亲本细胞谱系的比例。然而，整个补丁图案的复杂性应该取决于这个比例。嵌合体组织内斑块空间分布的复杂性也应取决于两个亲本谱系的比例。我们测量了嵌合体大鼠肝脏中斑块边界的复杂性（表面分形维数）、斑块整个区域的复杂性（质量分形维数）以及斑块空间分布的复杂性（分形碎片）。我们已经确定，表面分形维数不会随着嵌合体组织中两个亲本谱系的比例变化而变化，整个斑块的复杂性与该比例之间存在简单的关系，并且斑块是分形碎片化的。这些结果与重复应用这种简单的细胞分裂程序导致肝实质产生的假设是一致的。
In the development of mammalian organs, a rapid and robust expansion of the parenchymal compartment must occur following allocation of organ primordia. This expansion must be regulated so that sufficient tissue mass is generated for further organization into functional tissues. The discovery that mosaic patches in the liver of rat chimeras are fractal (a geometric form with characteristic complexity) suggests a possible information storage scheme for programs of parenchyma generation. Since fractal objects are produced by the repetitive application of specific rules, it is possible that such a mechanism is responsible for the generation of organ parenchyma. The model cell division program for the generation of organ parenchyma considered here is to choose a cell at random to divide and place the daughter cell in a randomly chosen adjacent position displacing other cells which might occupy the chosen position. The completion of the division creates a new population of cells representing the input conditions for the next division. When this is repeated over and over in a tissue comprising two genetically distinguishable populations of cells, analysis of the geometry of the mosaic pattern obtained should fulfill specific predictions. If cell division occurred in this manner, the complexity of patch boundaries (patches are contiguous aggregates of cells of the same marker lineage in tissue from a chimera) should be independent of the proportion of the two parental cell lineages which make up the chimera's tissue. However, the complexity of the entire patch pattern should be dependent on this proportion. The complexity of the spatial distribution of the patches within a chimera's tissue should also be dependent on the proportion of the two parental lineages. We have measured the complexity of patch boundaries (surface fractal dimension), the complexity of entire fields of patches (mass fractal dimension), and the complexity of the spatial distribution of patches (fractal fragmentation) in rat liver from chimeras. We have established that the surface fractal dimension does not change as the proportion of the two parental lineages in the chimera's tissue changes, that there is a simple relationship between the complexity of entire patches and this proportion, and that the patches are fractally fragmented. These results are consistent with the hypothesis that repetitive application of this simple cell division program accounts for the generation of liver parenchyma.