Development of Environmental Risk Assessment System

DNA微阵列技术是测定药物和环境化学物质等外源物对细胞或实验动物毒理学影响的有效方法。为了阐明DNA微阵列方法对野生动物样本的有效性，我们从日本的城市地区、垃圾填埋场和孤岛收集了野生挪威大鼠（大鼠）。实验大鼠（Wistar）作为对照动物。我们测量了多氯二苯并对二恶英（PCDD）、呋喃（PCDF）、多氯联苯（PCBs）和有机氯杀虫剂的积累水平。我们还检查了大鼠肝脏中多溴联苯醚（PBDE）的残留水平，多溴联苯醚是塑料和橡胶中的阻燃剂。此外，我们利用DNA芯片技术筛选了野生大鼠肝脏和睾丸中mRNA的变化，并报道了污染物积累与RNA表达谱的关系。在这项研究中，我们也展示了可以作为生物标志物的基因。为了开发野生动物的DNA芯片，我们收集了野生动物和圈养动物的样本来比较基因序列。我们克隆了广谱哺乳动物、鸟类和两栖动物的P450基因和核受体基因。我们阐明了在几种野生动物中开发微阵列的可能性。在目前的研究中，我们还旨在建立能够评估环境化学物质对核受体亲和力的功能阵列。我们测定了核受体的配体亲和力和异种受体之间的串扰，如芳烃受体、组成型活性受体和过氧化物酶体增殖体激活受体。

The DNA microarray techniques are useful method to determine toxicological effects of xenobiotics, such as drugs and environmental chemicals, on the cells or experimental animals. To clarify the usefulness of DNA microarray method for wildlife samples, we collected wild Norway rats (rats) from urban areas, landfill and isolated island in Japan. Laboratory rats (Wistar) were used as control animals in this study. We measured the accumulation levels of polychlorinated dibenzo-p-dioxins (PCDD), furans (PCDF), polychlorinated biphenyls (PCBs), and organochlorine insecticides. We also examined the residue levels of polybrominated diphenyl ether (PBDE) in rat livers, which are used as flame retardants in plastics and rubbers. Additionally, we screened the alterations of mRNA in liver and testis of wild rats using DNA chip technique, and reported the relationships between accumulated contaminants and expression profiles of RNA. In this study, we also showed the genes which can be used as biomarkers.To develop the DNA microarray for wild animals, we collected samples of wild and captive animals to compare the gene sequences. We cloned P450 and nuclear receptor genes from broad spectrum mammalians, birds and amphibians. We elucidated the possibility of microarray development for several wildlife species.In current study, we also aimed at establishment of functional array which can assess the affinity of environmental chemicals to nuclear receptors. We determined the ligand affinities of nuclear receptors and cross-talk among xenobiotic receptors, e.g., arylhydrocarbon receptor, constitutive active receptor and peroxisome proliferator-activated receptors.