Schumacher Fabian, Florian Simone, Schnapper Anke, Monien Bernhard H, Mewis Inga, Schreiner Monika, Seidel Albrecht, Engst Wolfram, Glatt Hansruedi
German Institute of Human Nutrition, Potsdam-Rehbrücke, 14558, Nuthetal, Germany.
Arch Toxicol. 2014 Mar;88(3):823-36. doi: 10.1007/s00204-013-1149-7. Epub 2013 Oct 24.
1-Methoxy-3-indolylmethyl (1-MIM) glucosinolate, a secondary metabolite of Brassicales species, and its breakdown product 1-MIM alcohol are mutagenic in cells in culture after activation by plant β-thioglucosidase and human sulphotransferase, respectively. In the present study, we administered these compounds orally to mice to study time course, dose dependence, tissue distribution and cellular localization of the 1-MIM DNA adducts formed. We used isotope-dilution ultra-performance liquid chromatography-tandem mass spectrometry to quantify the adducts and raised an antiserum for their immunohistochemical localization. Both compounds formed the same adducts, N(2)-(1-MIM)-2'-deoxyguanosine and N(6)-(1-MIM)-2'-deoxyadenosine, approximately in a 3.3:1 ratio. 1-MIM glucosinolate primarily formed these adducts in the large intestine, with a luminal-basal gradient, probably due to activation by thioglucosidase from intestinal bacteria. 1-MIM alcohol formed higher levels of adduct than the glucosinolate. Unlike after treatment with the glucosinolate, luminal and basal enterocytes were similarly affected in caecum, and liver and stomach were additional important target tissues. Maximal adduct levels were reached 8 h after the administration of both compounds. The hepatic DNA adducts persisted for the entire observation period (48 h), whereas those in large intestine rapidly declined due to cell turnover, as verified by immunohistochemistry. Hepatic adduct formation was focused on the periportal hepatocytes with concomitant depletion of glycogen, p53 activation and p21 induction. Adduct formation in caecum was associated with massive apoptosis, p53 activation and p21 induction, in particular after treatment with 1-MIM alcohol. It remains to be studied whether similar effects occur in humans after the consumption of Brassicales species.
1-甲氧基-3-吲哚甲基（1-MIM）硫代葡萄糖苷是十字花目植物的一种次生代谢产物，其分解产物1-MIM醇分别经植物β-硫代葡萄糖苷酶和人磺基转移酶激活后，在培养细胞中具有致突变性。在本研究中，我们给小鼠口服这些化合物，以研究形成的1-MIM DNA加合物的时间进程、剂量依赖性、组织分布和细胞定位。我们使用同位素稀释超高效液相色谱-串联质谱法定量加合物，并制备了抗血清用于其免疫组织化学定位。两种化合物形成相同的加合物，即N(2)-(1-MIM)-2'-脱氧鸟苷和N(6)-(1-MIM)-2'-脱氧腺苷，比例约为3.3:1。1-MIM硫代葡萄糖苷主要在大肠中形成这些加合物，具有从肠腔到基底的梯度，这可能是由于肠道细菌的硫代葡萄糖苷酶激活所致。1-MIM醇形成的加合物水平高于硫代葡萄糖苷。与硫代葡萄糖苷处理后不同，盲肠中的肠腔和基底肠上皮细胞受到的影响相似，肝脏和胃也是另外重要的靶组织。两种化合物给药后8小时达到最大加合物水平。肝脏中的DNA加合物在整个观察期（48小时）内持续存在，而大肠中的加合物由于细胞更新而迅速下降，免疫组织化学证实了这一点。肝脏加合物的形成集中在门周肝细胞，同时伴有糖原消耗、p53激活和p21诱导。盲肠中的加合物形成与大量细胞凋亡、p53激活和p21诱导有关，尤其是在用1-MIM醇处理后。食用十字花目植物后人类是否会出现类似效应仍有待研究。
