Madara J L, Stafford J, Dharmsathaphorn K, Carlson S
Gastroenterology. 1987 May;92(5 Pt 1):1133-45. doi: 10.1016/s0016-5085(87)91069-9.
Confluent monolayers of epithelial cell lines of intestinal derivation may serve as useful models for studies of intestinal epithelial structure and function. Cells of the T84 line appear to be a useful model for studies of Cl- secretion. We now define the fine structure of this cell line, the structural events that occur during monolayer formation, and the influence of plastic versus collagen substrates and permeable versus impermeable substrates on the structural development of these monolayers. When plated on collagen-coated filters at confluency, T84 cells cover the filter surface and lay down basement membrane-like material within 18 h. Such "monolayers" multifocally display areas with many cell layers alternating with areas composed of a single layer of cells. During this stage of development cell polarization is minimal, ultrastructural discontinuities exist that impart low transepithelial resistance, and morphologic features reminiscent of stratified intestinal epithelium during fetal development are present. Within 5 days of plating on collagen-coated filters, true monolayers form. These monolayers have high transepithelial resistance and consist of highly polarized columnar cells with structural similarity to intestinal crypt cells. Cells plated on a plastic substrate are also capable of rapidly producing basement membrane-like material but, unlike those plated on collagen-coated filters, under these conditions the rapid initial spreading of cells over the substrate surface does not occur. As a result, at 5 days monolayers plated on plastic are less uniform than those plated on collagen-coated filters, exhibit areas in which unpolarized flattened cells abound, and multifocally leak macromolecules. Studies using collagen-coated filters made impermeant with glass backing suggest that the enhancing effect of this substrate on monolayer structural development is not simply due to the greater access that basolateral membranes have to nutrient media when grown on permeable supports. This study defines the structure and structural development of this useful model epithelium, and demonstrates the importance of substrate selection.
肠道来源的上皮细胞系汇合单层可作为研究肠道上皮结构和功能的有用模型。T84细胞系的细胞似乎是研究氯离子分泌的有用模型。我们现在定义该细胞系的精细结构、单层形成过程中发生的结构事件，以及塑料与胶原基质以及可渗透与不可渗透基质对这些单层结构发育的影响。当在胶原包被的滤器上汇合接种时，T84细胞覆盖滤器表面，并在18小时内沉积类似基底膜的物质。这样的“单层”多处显示出有许多细胞层的区域与由单层细胞组成的区域交替出现。在这个发育阶段，细胞极化最小，存在超微结构的间断，导致跨上皮电阻较低，并且存在类似于胎儿发育期间分层肠道上皮的形态学特征。在胶原包被的滤器上接种后5天内，形成真正的单层。这些单层具有高跨上皮电阻，由与肠道隐窝细胞结构相似的高度极化的柱状细胞组成。接种在塑料基质上的细胞也能够快速产生类似基底膜的物质，但与接种在胶原包被的滤器上的细胞不同，在这些条件下，细胞不会在基质表面迅速初始铺展。结果，在5天时，接种在塑料上的单层比接种在胶原包被的滤器上的单层更不均匀，存在许多未极化扁平细胞的区域，并且多处泄漏大分子。使用带有玻璃背衬使其不可渗透的胶原包被滤器的研究表明，这种基质对单层结构发育的增强作用不仅仅是由于在可渗透支持物上生长时基底外侧膜对营养培养基有更大的接触机会。本研究定义了这种有用的模型上皮细胞的结构和结构发育，并证明了基质选择的重要性。
