Hodin R A, Chamberlain S M, Meng S
Department of Surgery, Beth Israel Hospital, Boston, Massachusetts, USA.
Am J Physiol. 1995 Aug;269(2 Pt 1):C385-91. doi: 10.1152/ajpcell.1995.269.2.C385.
Enterocyte growth and differentiation occur simultaneously within the epithelium, but little is known regarding any relationship between these two processes. Four rat models of small intestinal epithelial hypo- and hyperplasia (neonatal ontogeny, fasting/refeeding, hypo-/hyperthyroidism, and bombesin treatment) were used to study the regulation of enterocyte gene expression in relation to epithelial growth state. Mucosal scrapings, as well as crypt and villus cell populations, were subjected to Northern blot analyses using radiolabeled cDNA probes corresponding to lactase, intestinal alkaline phosphatase, villin, ornithine decarboxylase (ODC), and the actin control. In all four models, the hypoplastic (atrophic) condition is characterized by high levels of lactase and low levels of the 3.0-kb intestinal alkaline phosphatase mRNA, whereas under hyperplastic conditions this pattern is reversed. The changes in intestinal alkaline phosphatase and lactase are qualitatively similar along the longitudinal axis of the intestine and are proportional to the degree of hyperplasia, as verified by ODC mRNA levels. Furthermore, the crypt-villus axis of differentiation is maintained regardless of epithelial growth state. In conclusion, the pattern of brush-border enzyme gene expression changes as a function of epithelial growth state, indicating a previously unrecognized degree of plasticity to the state of enterocyte differentiation.
肠上皮细胞的生长和分化在肠上皮内同时发生，但这两个过程之间的关系却鲜为人知。本研究使用了四种小肠上皮增生和发育不全的大鼠模型（新生个体发育、禁食/再喂食、甲状腺功能减退/亢进以及蛙皮素处理）来研究肠上皮细胞基因表达与上皮生长状态之间的调控关系。使用对应乳糖酶、肠碱性磷酸酶、绒毛蛋白、鸟氨酸脱羧酶（ODC）的放射性标记cDNA探针以及肌动蛋白对照，对黏膜刮片、隐窝细胞群和绒毛细胞群进行Northern印迹分析。在所有四种模型中，发育不全（萎缩）状态的特征是乳糖酶水平高，而3.0kb肠碱性磷酸酶mRNA水平低，而在增生状态下这种模式则相反。肠碱性磷酸酶和乳糖酶的变化沿肠道纵轴在质量上相似，并且与增生程度成比例，这一点通过ODC mRNA水平得到证实。此外，无论上皮生长状态如何，隐窝-绒毛分化轴均得以维持。总之，刷状缘酶基因表达模式随上皮生长状态而变化，这表明肠上皮细胞分化状态具有此前未被认识到的可塑性程度。
