太湖背角无齿蚌组织中8-羟基脱氧鸟苷的含量及在水体污染评价中的初步应用

对2003--2008年闯采集自太湖不同水域的9个背角无齿蚌（Anodontawoodiana）样品组织中的DNA损伤产物-8-羟基脱氧鸟苷（8-hydroxy-2-deoxyguanosine，8-OHdG）的水平进行了分析，同时研究了蚌体组织中重金属cd2＋和有机污染物PCBs的蓄积残留量，以探明水体污染和DNA损伤的相关性。研究结果显示，9个样本中的8-OHdG的含量在1．021-8．886ng．g-1之间，尤其以无锡三山岛和宜兴大浦这2个水域的样本最为突出，差异显著，表明上述水域已受到较严重的污染。PCBs在9个样本中有7个检出，但含量无明显差异（P〉0．05），表明PCBs并非引起背角无齿蚌体内DNA损伤的主要污染因素。而背角无齿蚌组织中的cd2＋残留量与8-OHdG水平间存在显著的剂量一效应关系，呈正相关。这一结果与实验室内的模拟试验相吻合，提示重金属cd2＋是引起水体中背角无齿蚌DNA受损的主要污染因素。研究显示，背角无齿蚌机体组织中的8-OHdG具有稳定性强、测定方法简单快速、在一定的范围内具有显著的剂量—效应关系、实验室与野外分析相吻合等特点，因此可作为分子生物标志物来评价生物体受水环境持久性污染物污染而导致的DNA损伤效应。

Level of 8-hydroxy-2-deoxyguanosine in swan mussels Anodonta woodiana from Taihu Lake and its preliminary application to assess water pollution

With the aim of investigating the relationship between water pollution and DNA damage in aquatic organism, the residuals of heavy metal Cd2＋ and organochlorine PCBs were measured and the 8-hydroxy-2-deoxyguanosine （8-OhdG, a marker of oxidative damage to DNA） levels were evaluated in nine swan mussels Anodonta woodiana collected from different sites in the Taihu Lake, China. The levels of 8-OhdG of the mussels were 1.021-8.886 ng.g-1 and especially higher for those from the sites of Sanshandao of Wuxi city and Dapu of Yixing city, suggesting a more serious pollution in these sites of the Taihu Lake. PCBs were detected in seven of the nine mussels, and however, the residual contents did not show any site differences, implying PCBs might not be the major contamination factor causing DNA damage in A. woodiana. Contrastly, a significant positive dose-effect of tissular Cd2＋ residual contents on 8-OhdG levels was found in both field and laboratory research, indicating that Cd2＋ should play a major role in DNA damage ofA. woodiana. The 8-OhdG could be applicable for assessing oxidative damage to DNA in aquatic organism, as this oxi- dized nucleoside of DNA in A. woodiana of the present study was stable, easy and rapid to measure, and had a significant positive dose-effect with a better field- laboratory agreement.