Department of Biology, McMaster University, Hamilton, ON, Canada.
Ecotoxicol Environ Saf. 2013 Feb;88:95-102. doi: 10.1016/j.ecoenv.2012.10.028. Epub 2012 Dec 5.
This study links results from past in vitro and in vivo experiments, by implementing an in situ experiment in order to determine the relative importance for cadmium (Cd) uptake of different sections of the gastro-intestinal tract (GIT) of rainbow trout. Transport of Cd from four sections of the GIT of adult rainbow trout (~220 g) was individually examined by infusing ligated sections of the GIT in live, free-swimming fish with 50 μM Cd spiked with radiolabelled (109)Cd (0.5 μCi ml(-1)). Fish were exposed for an 8-h period. The percentage of the total injected (109)Cd which was internalized from the different segments was only between ~0.1 and ~7%, indicating low uptake efficiency. The stomach is the most important GIT segment for Cd transport into the internal compartment of the animal, while the posterior intestine also plays a significant role. The majority of (109)Cd recovered at the end of the flux period was detected within gut material (ranging from 28 to 95%); the portion of Cd which was internalized was largely found in the carcass (32 to 60%). Distribution between the measured organs varied with uptake from the various GIT sections. Our results also confirm that the GIT acts as a protective barrier against Cd uptake from dietary exposure.
本研究通过在原位实验中，将过去的体外和体内实验结果联系起来，以确定镉（Cd）在虹鳟鱼胃肠道（GIT）不同部位吸收的相对重要性。通过用放射性标记的（109）Cd（0.5 μCi ml（-1））对成年虹鳟鱼（220 g）的 GIT 的结扎部位进行灌流，单独检查 GIT 的四个部位中 Cd 的转运。将鱼暴露在 8 小时内。从不同部位内化的总注射（109）Cd 的百分比仅在0.1 到~7%之间，表明吸收效率低。胃是 Cd 向动物内部腔室转运的最重要的 GIT 部位，而后肠也起着重要作用。在通量期结束时回收的大部分（109）Cd 存在于肠道物质中（范围为 28 至 95%）；内化的 Cd 大部分存在于胴体中（32 至 60%）。各个 GIT 部位的吸收分布在测量器官之间存在差异。我们的结果还证实，GIT 是防止膳食暴露中 Cd 吸收的保护屏障。
