Biomembrane Laboratory, Industrial Toxicology Research Centre, Mahatma Gandhi Marg, Lucknow, 226001India.
Toxicol Mech Methods. 2005;15(5):331-8. doi: 10.1080/153765291009804.
Toxicants including heavy metals reaching the intestine following ingestion through food and water primarily interact with an ecosystem of eukaryotic and prokaryotic cells. Gut bacteria having a dynamic interrelationship with intestinal epithelial cells are known to play important and specific metabolic, trophic, and protective functions. The present study was undertaken to compare the effects of hexavalent chromium on rat intestinal epithelial cells and the resident gut bacteria following in vitro and in vivo exposures. The survival rate and viability pattern of two types of cells were comparable. Under in vitro conditions, the gut bacteria were quick to reduce Cr (VI) in early time periods, while, at 30 h time, both types of cells showed similar capacity for the reduction of Cr (VI). Chromium intoxication (10 ppm of Cr (VI) in drinking water for 10 weeks) caused significant decrease in membrane alkaline phosphatase and Ca(2 +)-Mg(2 +)-ATPase activities of intestinal epithelial cells as well as of three gut bacteria viz. Escherichia coli, Pseudomonas sp, and Lactobacillus sp. Major structural membrane constituents like carbohydrates and phospholipids also showed significant decline in both types of cells. These findings indicate that 10 ppm and higher Cr concentrations may cause toxic insult, resulting in impaired intestinal functional efficacy. It also implies that the gut bacteria can be used at least for preliminary screening of heavy metals gastrointestinal toxicity.
摄入食物和水后，包括重金属在内的毒物首先会与真核细胞和原核细胞的生态系统相互作用。肠道细菌与肠上皮细胞之间存在着动态的相互关系，已知它们具有重要的、特定的代谢、营养和保护功能。本研究旨在比较六价铬在体外和体内暴露后对大鼠肠上皮细胞和肠道常驻细菌的影响。两种细胞的存活率和活力模式相似。在体外条件下，肠道细菌能迅速在早期还原 Cr(VI)，而在 30 小时时，两种类型的细胞都显示出相似的还原 Cr(VI)的能力。铬中毒（饮用水中 Cr(VI)浓度为 10 ppm，持续 10 周）导致肠上皮细胞的膜碱性磷酸酶和 Ca(2 +)-Mg(2 +)-ATP 酶活性以及三种肠道细菌（大肠杆菌、假单胞菌和乳酸杆菌）显著下降。两种细胞的主要结构膜成分，如碳水化合物和磷脂，也显著下降。这些发现表明，10 ppm 及更高浓度的 Cr 可能会造成毒性损伤，导致肠道功能受损。这也意味着肠道细菌至少可以用于重金属胃肠道毒性的初步筛选。
