典型水污染区环境样品的去甲基化表观遗传毒性初步研究

A Preliminary Study on Demethylation Epigenetic Toxicity of Environmental Samples from Typical Water-polluted Area

摘要：从去甲基化能力方面研究地表水、地下水、土壤等环境样品综合表观遗传毒性。将pEGFP—C3质粒通过人工甲基化处理获得荧光蛋白基因启动子区处于高甲基化状态的c3质粒，并将其转染进人类HepG一2肝癌细胞株，随后以该改造细胞株（EGF—PHepG2）为主要工具载体，与样品提取液进行共培养，依据细胞绿色荧光强度来定量评价样品的去甲基化功能的强弱（简称EGFP方法）。同时通过电感耦合等离子体质谱法（ICP／MS）对样品提取液的成分进行扫描检测分析。结果表明，在9个测试样中，有7个显示出可以观察到的去甲基化表观遗传毒性，占测试样品的78％。其去甲基化表观遗传毒性当量介于0．065～0257m01·L。的5-Aza．CdR之间。在4个存在超标的土壤或底泥样品中，有3个被检测出具有可以观察到的去甲基化表观遗传毒性，环境样品表观遗传毒性检测结果也与环境分析结果具有基本一致的趋势。结果初步显示，部分环境样品去甲基化能力较强，具有不容忽视的表观遗传毒性。

The integrated epigenetic toxicity of environmental samples including surface water, groundwater and soil was studied from the aspect of demethylation capacity. By artificial methylated processing, pEGFP-C3 plasrnid was obtained C3 plasmid whose fluorescent protein gene promoter region was highly methylated and then transfected into HepG-2 cells. As transfection had been finished, the transfected cell strain （EGFR HepG2） as the main tool cartier was co-cultured with test substance. Finally, quantitative evaluation based on the green fluorescence intensity of cells can be used to measure the demethylating function of the test chemical. At the same time, composition of the sample extraction was scanned, detected and analyzed by inductively coupled plasma mass spectrometry （ICP/MS）. There were seven of the nine test samples showing strong dem- ethylation epigenetic toxicity, whose range on demethylation epigenetic toxic equivalency was from 0.065 to 0257 ~mol＇L1 5-Aza-CdR, accounting for 78% of the total nine samples. Among four samples with excessive standard content from soil or sediment, observable demethylation epigenetic toxicity can be detected in three samples. Finally, test results from environmental samples epigenetic toxicity had a basically consistent trend with environmental analysis results. The results indicated that a part of environmental samples with non-negli- gible epigenetic toxicity had good ability of demethylation.