模拟高原缺氧环境对大鼠小肠组织病理和肠黏膜通透性的影响

目的探讨模拟高原环境对大鼠小肠黏膜形态结构和超微结构的影响,并通过双糖吸收实验考察肠黏膜通透性的改变。方法利用减压舱模拟5 500 m海拔高度,缺氧处理3周后,光镜及透视电镜下观察小肠黏膜上皮细胞形态结构和超微结构的变化。采用HPLC法检测研究对象尿液标本中甘露醇和乳果糖排出率比值。结果与实验对照组比较,高海拔缺氧组大鼠小肠黏膜变薄、肠黏膜水肿、绒毛短缩;超微结构也显示线粒体肿胀、嵴稀疏或消失,微绒毛变短、倒伏和部分缺失,且肠黏膜细胞凋亡也较常见。高海拔缺氧组肠道的通透性显著高于实验对照组（P〈0.01）。结论高原缺氧环境可导致小肠黏膜损伤,肠黏膜通透性增加,肠黏膜屏障破坏。

Effects of hypoxia on intestinal permeability and small intestinal histopathology in rats exposed to high altitude

Objective To observe the histological and ultrastructural changes of intestinal mucosa in rats exposed to high altitude and to evahlate the intestinal perineability by two-sugar absorption test with a specific high performance liquid chromatography （HPLC）. Methods Rats were exposed to 5 500 m high ahitude in a hypobaric chamber. After 3 weeks, the morphological changes of intestinal nmcosa were observed under light and transmission electron microscopy （TEM）. Urine samples were collected by HPLC. The excretion rate of mannite to tile excretion rate of lactulose （L/M） was calculated. Results After exposed to high attitude of hypoxia, the intestinal endothelial cells showed a series of pathological injuries, including mucosal thinning, hydropsia and villus shortening. TEM observation indicated a shorter, lodging, partial absence of microvilli on the surface of absorptive cell and mitochondria swelling, mitochondrial cristae sparse or disappear. The apoptosis of intestiual mucosal cells was also commonly observed. The enteric permeability in hypoxia group was higher than that in control group （P 〈 0.01 ）. Conclusion Exposure to high altitude can influence mucosa structure of small intestine, increase the intestinal permeability and damage the intestinal mueosal barrier.