CONGENITAL MEGACOLON--TISSUE INTERACTION IN DEVELOPMENT

致死性斑点突变小鼠(1S/1S)在A近端发育成巨结肠 无神经节终末肠段。无神经节组织似乎 从细胞体位于外面的神经元接受轴突的神经支配 我的直觉。内源性肠神经元的胞体和突起， 然而，它们被排除在无神经节区域之外。我们以前使用过 器官型组织培养揭示神经元的分布 正常和1s/1s胎鼠肠道中的前体细胞。神经元在体内发育 培养，如果在肠道中存在可存活的前体时 解释一下。这些实验已经揭示了终端2毫米的 任何年龄的突变小鼠的肠道都不会产生神经元化 外植体，尽管正常小鼠的整个肠道都会这样做 早在E9天。我们提出，作为一种假设来解释这一派生 在1s/1s动物中的无神经节细胞增多症，即 1s/1s小鼠肠道末端2 mm异常，不允许 肠神经前体细胞在该区域的定植。这 假设需要检验，如果得到证实，我们将尝试确定 这个缺陷。以下问题将由拟议的 研究。(1)神经元前体是否未能进入终末2 mm 1s/1s肠道，还是进入这个区域并死亡？神经丝 免疫反应性可作为肠神经前体的标志物 细胞。(2)肠神经胶质细胞前体细胞是否不能进入(或存活 1s/1s肠管末端2 mm？神经胶质纤维的免疫反应性 酸性蛋白将被用作神经胶质标记物。(3)是 末端2 mm的1s/1s肠异常？是细胞外基质蛋白 1s/1s肠末端2 mm异常？免疫细胞化学 将对组织进行检查，以确定 纤维连接蛋白、层粘连蛋白、I型和IV型胶原。这些实验是 旨在利用突变小鼠的缺陷来洞察 组织间的相互作用在神经导数发育中的作用 克雷斯特。

The lethal spotted mutant mouse (1S/1S) develops megacolon proximal to a segment of aganglionic terminal bowel. The aganglionic tissue appears to receive an innervation of axons from neurons whose cell bodies lie outside the gut. The cell bodies and processes of intrinsic enteric neurons, however, are excluded from the aganglionic region. We have previously used organotypic tissue cultures to reveal the distribution of neuronal precursors in the normal and 1S/1S fetal mouse gut. Neurons develop in culture if viable precursors are present in the gut at the time of explanation. These experiments have revealed that the terminal 2 mm of bowel from mutant mice at any age will never give rise to neuralized explants in culture, although the entire gut of normal mice will do so as early as day E9. we propose, as a hypothesis to account for the derivation of aganglionosis in 1S/1S animals, that the microenvironment of the terminal 2mm of bowel is abnormal in 1S/1S mice and does not permit the colonization of that region with enteric neuronal precursor cells. This hypothesis is to be tested and, if confirmed, we will attempt to identify the defect. The following questions will be answered by the proposed research. (1) Do neuronal precursors fail to enter the terminal 2 mm of 1S/1S bowel or do they enter this region and die? Neurofilament immunoreactivity will be used as a marker for enteric neuronal precursor cells. (2) Do precursors of enteric glial cells fail to enter (or survive in) the terminal 2 mm of 1S/1S bowel? Immunoreactivity of glial fibrillary acid protein will be used as a glial marker. (3) Is the structure of the terminal 2 mm of 1S/1S bowel abnormal? Are extracellular matrix proteins abnormal in the terminal 2 mm of 1S/1S bowel? Immunocytochemical examination of tissues will be done to determine the distribution of fibronectin, laminin, and types I and IV collagen. These experiments are designed to exploit the defect of the mutant mouse to gain insight into the role of tissue interactions in the development of derivatives of the neural crest.