Roesijadi G, Rezvankhah S, Perez-Matus A, Mitelberg A, Torruellas K, Van Veld P A
Florida Atlantic University, Department of Biological Sciences, Boca Raton, FL 33431, USA.
Mar Environ Res. 2009 Feb;67(1):25-30. doi: 10.1016/j.marenvres.2008.10.002. Epub 2008 Oct 17.
Fish were individually fed food pellets containing cadmium, benzo(a)pyrene, or a combination of the two, then analyzed for metallothionein mRNA expression in the intestine, liver, and gill using real-time RT-qPCR. An initial experiment using only cadmium showed that ingestion of pellets varied in individual fish, and estimates of cadmium dose from the numbers of ingested pellets indicated considerable individual variability in cadmium dose. Induction of intestinal metallothionein mRNA was apparent, however, and a linear dose-response relationship was observed for metallothionein expression and cadmium dose in the intestine, but not the other organs, which showed no induction. In a second experiment, the entire daily cadmium dose was provided in a single contaminated pellet that was consumed by all treated fish, effectively eliminating the effect of variable ingestion rates on dose, and the interaction between cadmium and benzo(a)pyrene was also investigated. The intestine was again the primary organ for metallothionein induction by cadmium. When benzo(a)pyrene was administered together with cadmium, induction of metallothionein was potentiated by the presence of benzo(a)pyrene, with the main effect seen in the intestine, where already high levels of induction by cadmium alone increased by 1.74-fold when benzo(a)pyrene was present.
分别给鱼投喂含有镉、苯并(a)芘或两者组合的鱼食颗粒，然后使用实时逆转录定量聚合酶链反应（RT-qPCR）分析肠道、肝脏和鳃中金属硫蛋白mRNA的表达。最初仅使用镉的实验表明，每条鱼摄入的鱼食颗粒数量不同，根据摄入颗粒数量估算的镉剂量显示，镉剂量存在相当大的个体差异。然而，肠道金属硫蛋白mRNA的诱导是明显的，并且在肠道中观察到金属硫蛋白表达与镉剂量之间存在线性剂量反应关系，但在其他器官中未观察到诱导现象。在第二个实验中，将全部每日镉剂量包含在一个被所有处理过的鱼食用的受污染单一鱼食颗粒中，有效消除了摄食率变化对剂量的影响，并且还研究了镉与苯并(a)芘之间的相互作用。肠道再次成为镉诱导金属硫蛋白的主要器官。当苯并(a)芘与镉一起给药时，苯并(a)芘的存在增强了金属硫蛋白的诱导作用，主要作用见于肠道，在肠道中，仅镉诱导的高水平已经增加了1.74倍，当存在苯并(a)芘时。
