Toda S, Sugihara H
Department of Pathology, Saga Medical School, Japan.
Endocrinology. 1990 Apr;126(4):2027-34. doi: 10.1210/endo-126-4-2027.
Thyroid follicles, an essential functional unit of the thyroid, are ball-like structures and exist in the extracellular matrix in vivo. Thus far, the follicles have not been reconstructed in any culture system. The presumed reason for that was that the in vitro environment for the follicle cells in monolayer culture markedly differed from their environment in vivo. We, therefore, considered that isolated follicle cells had to be localized in a three-dimensional environment of extracellular matrix, specifically collagen, to reconstruct thyroid follicles in vitro. At first, follicle cells were completely isolated. These cells were cultured in the three-dimensional collagen gel. An intracytoplasmic cavity first developed in individual cells. A single cell with the cavity then underwent cell division, and the follicle consisting of two cells was reconstructed. This gradually grew to be a large ball-like structure through proliferation of the component cells, and they exhibited morphological polarity specific for thyroid follicle cells. In addition, these cells clearly produced thyroid hormones. To the best of our knowledge, this report is the first instance of reconstruction of thyroid follicles in an in vitro culture system. This culture system is more useful than the monolayer culture system in that this system provides a more physiological environment for investigations of differentiation of follicle cells. Further experiments using this method will probably provide a new clue to the mechanism of thyroid folliculogenesis.
甲状腺滤泡是甲状腺的基本功能单位，呈球状结构，在体内存在于细胞外基质中。迄今为止，尚未在任何培养系统中重建出滤泡。推测其原因是单层培养中滤泡细胞的体外环境与体内环境明显不同。因此，我们认为分离的滤泡细胞必须定位在细胞外基质的三维环境中，特别是胶原蛋白中，才能在体外重建甲状腺滤泡。首先，滤泡细胞被完全分离出来。这些细胞在三维胶原凝胶中培养。单个细胞内首先形成胞质腔。然后，带有胞质腔的单个细胞进行细胞分裂，从而重建出由两个细胞组成的滤泡。通过组成细胞的增殖，这个滤泡逐渐生长为一个大的球状结构，并且它们表现出甲状腺滤泡细胞特有的形态极性。此外，这些细胞明显分泌甲状腺激素。据我们所知，本报告是首次在体外培养系统中重建甲状腺滤泡。该培养系统比单层培养系统更有用，因为它为滤泡细胞分化的研究提供了更接近生理状态的环境。使用这种方法进行的进一步实验可能会为甲状腺滤泡发生机制提供新的线索。
