EXTRACELLULAR MATRIX ALVEOLAR CELL DIFFERENTIATION

正常的骨髓间充质细胞和上皮细胞之间需要相互作用 许多组织的分化。细胞外基质可能参与了这一过程。 互动。我们建议调查两国关系的几个方面 肺泡上皮细胞和肺下间充质之间的关系 胎肺发育过程中的细胞外基质。这些研究将是 取自不同孕期胎儿的兔肺 年龄和体外模型，孕19天兔胎肺 在培养中保持的组织外植体，在该模型中，II型细胞 分化占主导地位。将使用超微结构形态计量学 以描述基底板的结构变化和物理 胎肺中间充质与上皮细胞的相互作用 发展。胎儿肺细胞外基质将在 利用光学和电子显微镜观察发育的不同阶段 细胞外基质的两种成分的免疫组织化学染色， 层粘连蛋白和纤维连接蛋白。在相关的生化研究中，我们将 测定层粘连蛋白和纤维连接蛋白的合成和积累率 在胎儿肺发育的不同阶段。一旦我们确定了 胎肺细胞外基质变化的正常模式 在发育过程中，我们将检查皮质醇的效果，皮质醇是一种 已知可加速胎肺发育，在形态和 上述生化参数。通过这种方式，我们可以确定 皮质醇对胎肺成熟的刺激作用部分是通过 间质和/或细胞外基质的变化。此外, 分散的胎肺细胞将在人工细胞外培养 肺内皮细胞或成纤维细胞产生的基质以及 层粘连蛋白、纤维连接蛋白和/或IV型胶原的基质。通过这种方式，我们 将确定似乎起作用的细胞外基质成分是否 在体内发育过程中起重要作用的是能够促进 在受控的体外环境中进行分化。这些研究的结果 研究将提供有关相互作用的重要信息 分化过程中细胞外基质与上皮细胞之间的关系 胎肺肺泡上皮细胞的变化，将有助于了解 组织分化的一般机制。更好地理解 正常的胎肺成熟过程可能会导致 更好的方法来刺激合适的风险胎儿的肺 这可能有助于预防出生后的RDS。

An interaction between mesenchyme and epithelium is required for the normal differentiation of many tissues. The extracellular matrix may mediate this interaction. We propose to investigate several aspects of the relationship between lung alveolar epithelial cells and the underlying mesenchyme and extracellular matrix during fetal lung development. These studies will be performed using rabbit lung obtained from fetuses of varying gestational ages, and an in vitro model, day 19 gestational age rabbit fetal lung tissue explants maintained in culture, a model in which type II cell differentiation is predominant. Ultrastructural morphometry will be used to describe changes in the structure of the basal lamina and physical interactions between mesenchyme and epithelium during fetal lung development. The fetal lung extracellular matrix will be described at the various stages of development by use of light and electron microscopic immunohistochemical staining for 2 components of the extracellular matrix, laminin and fibronectin. In correlative biochemical studies, we will determine the rate of synthesis and accumulation of laminin and fibronectin at different stages of fetal lung development. Once we have determined the normal pattern of changes in the extracellular matrix during fetal lung development, we will examine the effect of cortisol, a hormone which is known to accelerate fetal lung development, on the morphological and biochemical parameters described above. In this manner we can determine if cortisol stimulation of fetal lung maturation is mediated, in part, by changes in the mesenchyme and/or extracellular matrix. In addition, dispersed fetal lung cells will be cultured on artificial extracellular matrices produced by lung endothelial cells or fibroblasts as well as on matrices of laminin, fibronectin and/or type IV collagen. In this way we will determine if extracellular matrix components which appear to play an important role during development in vivo are capable of promoting differentiation in a controlled in vitro environment. The results of these studies will provide important information with respect to interactions between extracellular matrix and epithelial cells during differentiation of fetal lung alveolar epithelium and will be relevant to understanding the mechanisms of tissue differentiation in general. A better understanding of the process of normal fetal lung maturation could allow the development of better methods to stimulate the lung of the right risk-fetus in a manner that could serve to prevent RDS after birth.