Matovelo J A, Landsverk T, Sund R B
Department of Morphology, Genetics and Aquatic Biology, Norwegian College of Veterinary Medicine, Oslo.
APMIS. 1993 May;101(5):369-77. doi: 10.1111/j.1699-0463.1993.tb00123.x.
Loops of rat jejunum were exposed in vivo to different concentrations of deoxycholic acid (DOC; 0, 2.5, 5, 10 and 20 mM). Following a 30 min exposure period, DOC was washed out of the loops and the intestines were allowed to recover for 15 or 150 min. Frozen tissue for enzyme histochemistry was collected during exposure and following the recovery periods. As shown previously, exposure to DOC caused a dose-dependent loss of epithelial cells at the villous tips and denudation of the lamina propria. Flattened epithelial cells bordering the denuded areas were, however, responsible for a rapid restoration of epithelial continuity, which was completed within 15 min. In the present study, these flattened cells showed normal reactivity for non-specific esterase and succinate dehydrogenase. In contrast, following a prolonged recovery period (150 min), a subpopulation of enterocytes at the villous tips that otherwise appeared normal showed decreased reactivity for brush border enzymes and non-specific esterase, and a positive reaction for mucin. A shutdown in the synthesis of cytoplasmic enzymes and redistribution of cell surface enzymes could be responsible for these late occurring enzyme changes, that were consistently observed after 150 min of recovery from DOC at 20 mM. Alternatively, retention of goblet cells and/or a modification in enzyme synthesis may explain the presence of mucin that was demonstrated in the epithelial cells which had low enzyme reactivity.
将大鼠空肠袢在体内暴露于不同浓度的脱氧胆酸（DOC；0、2.5、5、10和20 mM）。暴露30分钟后，将DOC从肠袢中冲洗掉，让肠道恢复15或150分钟。在暴露期间以及恢复阶段后收集用于酶组织化学的冷冻组织。如先前所示，暴露于DOC会导致绒毛尖端的上皮细胞呈剂量依赖性丢失以及固有层剥脱。然而，与剥脱区域相邻的扁平上皮细胞负责上皮连续性的快速恢复，这在15分钟内完成。在本研究中，这些扁平细胞对非特异性酯酶和琥珀酸脱氢酶显示出正常反应性。相比之下，在延长的恢复阶段（150分钟）后，绒毛尖端原本看似正常的一部分肠细胞对刷状缘酶和非特异性酯酶的反应性降低，并且对粘蛋白呈阳性反应。细胞质酶合成的停止和细胞表面酶的重新分布可能是这些后期发生的酶变化的原因，在从20 mM DOC恢复150分钟后始终观察到这些变化。或者，杯状细胞的保留和/或酶合成的改变可能解释了在酶反应性较低的上皮细胞中显示出的粘蛋白的存在。
