Moore R, Carlson S, Madara J L
Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
Lab Invest. 1989 Feb;60(2):237-44.
Mild forms of intestinal epithelial injury commonly occur in many disease states. In order to study how such epithelial "wounds" heal, we have developed a highly reproducible in vitro model of intestinal epithelial injury. Guinea pig ileal mucosal sheets were mounted in Ussing chambers and the mucosal surfaces were exposed to 0.06% Triton-X 100 for 5 minutes. This resulted in denudation of the epithelium at the tips of 86% of villi. As a result of this injury, resistance to passive ion flow decreased significantly (56.5 +/- 1.3 versus 38.4 +/- 2.3 ohm.cm2 for control and injury, respectively, p less than 0.01), as did transepithelial potential difference (-11.9 +/- 0.7 versus -4.3 +/- 0.4 mV for control versus injury respectively, p less than 0.01). In parallel, transepithelial fluxes of the extracellular space markers mannitol and inulin increased 3- to 5-fold immediately after injury. Two hours after injury, villus tips were again confluently covered by columnar absorptive cells, a time course of healing too fast to be accounted for by enhanced cell proliferation. Analysis of the structural events occurring during recovery showed that absorptive cells shouldering the foci of denudation rapidly changed shape after injury: they became flattened and sent cell projections over the denuded basement membrane. By 60 minutes after injury, cells from opposite shoulders of the denudation abutted, thus resealing the defect. Paralleling these structural changes, transepithelial resistance, potential difference, and mannitol and inulin fluxes returned toward control values. These data show that focal epithelial discontinuities in the small intestine may be rapidly resealed. Such reparative processes may substantially limit the deleterious physiologic impact of superficial forms of intestinal injury.
轻度肠道上皮损伤在许多疾病状态中普遍存在。为了研究这种上皮“伤口”如何愈合，我们建立了一种高度可重复的肠道上皮损伤体外模型。将豚鼠回肠黏膜片安装在尤斯灌流小室中，使黏膜表面暴露于0.06%的 Triton-X 100 中5分钟。这导致86%的绒毛顶端上皮剥脱。由于这种损伤，被动离子流的阻力显著降低（对照组和损伤组分别为56.5±1.3和38.4±2.3 ohm·cm²，p<0.01），跨上皮电位差也降低（对照组和损伤组分别为-11.9±0.7和-4.3±0.4 mV，p<0.01）。同时，损伤后细胞外空间标记物甘露醇和菊粉的跨上皮通量立即增加3至5倍。损伤后两小时，绒毛顶端再次被柱状吸收细胞汇合覆盖，愈合的时间进程太快，无法用增强的细胞增殖来解释。对恢复过程中发生的结构事件分析表明，承担剥脱灶的吸收细胞在损伤后迅速改变形状：它们变平并向剥脱的基底膜上发出细胞突起。损伤后60分钟，来自剥脱灶相对两侧的细胞相互邻接，从而封闭缺损。与这些结构变化平行，跨上皮电阻、电位差以及甘露醇和菊粉通量恢复到对照值。这些数据表明，小肠中的局灶性上皮连续性中断可能会迅速封闭。这种修复过程可能会大大限制轻度肠道损伤形式的有害生理影响。
