Wells C L, Jechorek R P, Erlandsen S L
Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis 55455-0374.
Crit Care Med. 1995 Feb;23(2):301-7. doi: 10.1097/00003246-199502000-00016.
To clarify the effect of bile salts on internalization of enteric bacteria by intestinal epithelial cells.
Randomized study.
Research laboratory.
Cultured human intestinal epithelial cells, namely HT-29 cells.
The effect of bile was studied by adding bile during the time period in which bacterial cells were permitted to interact with enterocytes. In subsequent experiments, bile was added to the culture medium used to grow bacteria, and bacterial cells were washed before adding bacteria to enterocytes. Three different concentrations of three different bile preparations were tested.
Salmonella typhimurium and Proteus mirabilis were each incubated with HT-29 cells for 1 hr; the numbers of internalized bacteria were subsequently quantified following enterocyte lysis. The presence of bile during bacteria-enterocyte incubation had no effect on the numbers of internalized bacteria. However, if S. typhimurium or P. mirabilis were grown in the presence of bile, these washed bacterial cells were generally internalized by HT-29 cells in significantly fewer numbers, compared with bacterial cells grown in medium without bile supplementation. Enterocyte viability and morphologic ultrastructure did not appear to be affected by the presence of bile itself, or by the interaction with bacterial cells that had been cultivated in unsupplemented medium or in bile-supplemented medium.
Exposure to bile during bacterial growth resulted in bacterial cells with decreased invasiveness for cultured intestinal epithelial cells. This observation is consistent with previous in vivo studies of obstructive jaundice, where the absence of bile in the intestinal lumen, not bile duct ligation, appeared to facilitate bacterial translocation in obstructed animals. Thus, the presence of bile in the intestinal lumen may decrease bacterial translocation by a mechanism that involves decreased epithelial internalization of enteric bacteria.
阐明胆盐对肠道细菌被肠上皮细胞内化的影响。
随机研究。
研究实验室。
培养的人肠上皮细胞，即HT - 29细胞。
在细菌细胞与肠上皮细胞相互作用的时间段内添加胆汁，研究胆汁的作用。在随后的实验中，将胆汁添加到用于培养细菌的培养基中，并在将细菌添加到肠上皮细胞之前对细菌细胞进行洗涤。测试了三种不同胆汁制剂的三种不同浓度。
将鼠伤寒沙门氏菌和奇异变形杆菌分别与HT - 29细胞孵育1小时；随后在肠上皮细胞裂解后对内化细菌的数量进行定量。在细菌与肠上皮细胞孵育期间胆汁的存在对内化细菌的数量没有影响。然而，如果鼠伤寒沙门氏菌或奇异变形杆菌在胆汁存在的情况下生长，与在无胆汁补充培养基中生长的细菌细胞相比，这些洗涤后的细菌细胞通常被HT - 29细胞内化的数量明显减少。肠上皮细胞的活力和形态超微结构似乎不受胆汁本身的存在或与在未补充培养基或补充胆汁培养基中培养的细菌细胞相互作用的影响。
细菌生长过程中暴露于胆汁会导致细菌细胞对培养的肠上皮细胞的侵袭性降低。这一观察结果与先前关于梗阻性黄疸的体内研究一致，在梗阻性动物中，肠腔内胆汁的缺乏而非胆管结扎似乎促进了细菌移位。因此，肠腔内胆汁的存在可能通过一种涉及肠道细菌上皮内化减少的机制来减少细菌移位。
