两种有机酸存在下铜对中华圆田螺肝脏的氧化应激效应

The Oxidative Stress of Copper on Liver of River Snail Cipangopaludina cahayensis in the Presence of Two Kinds of Organic Acids

为探讨不同水平EDTA和柠檬酸(CA)作用下沉积物中铜对底栖无脊椎动物生态毒理学效应,以中华圆田螺为受试生物,研究了肝脏中活性氧(ROS)、丙二醛(MDA)含量、超氧化物歧化酶(SOD)以及过氧化氢酶(CAT)活性的变化规律。研究结果表明:有机酸存在下,铜污染底泥可诱导中华圆田螺肝脏产生ROS。电子顺磁共振(EPR)技术得出的3组双重峰分裂谱线为典型的α-苯基-N-叔丁基甲亚胺-N-氧化物(PBN)捕获羟自由基(·OH)形成PBN/·OH的EPR波谱。有机酸存在下,低剂量铜(≤100 mg·kg-1)对MDA产量影响不显著。较高剂量铜暴露下,EDTA的存在抑制MDA产生,CA的添加则均使MDA含量增加。EDTA存在下铜可显著抑制中华圆田螺肝脏中SOD和CAT活性。相对而言,CA的加入可减缓高剂量铜暴露下中华圆田螺肝脏SOD与CAT酶活性的剧烈变化。

The effects of EDTA or citric acid （CA） and malonaldehyde （MDA） content, superoxide dismutase copper in sediments on reactive oxygen species （ROS）, （SOD） and catalase （CAT） activities in liver of river snail, Cipangopaludina cahayensis were investigated to get insight into the ecotoxicological effects of copper in sediments with various gradient of EDTA or CA on benthic invertebrates. The results indicated that there was an obvious increase of ROS generation in liver of Cipangopaludina cahayensis treated with organic acids and copper compared with that of the control. The six-line composed of three groups with two hyperfme split-ting peaks in each showed a typical hydroxyl free radicals （. OH） spectrum, using electron paramagnetic resonance （EPR） spin trapping technique, captured by ot-phenyl-N-tert-butyinitron （PBN）. At copper concentration of 100 mg.kg-1and below, the content of EDTA and CA had no significant effect on MDA. EDTA inhibited the generation of MDA at higher concentration of copper. On the contrary, CA induced the generation of MDA at higher concentration of copper. EDTA could suppress the SOD and CAT activities in liver of Cipangopaludina cahayensis after copper exposure. In contrast, the addition of CA could avoid the severe changes of SOD and CAT activities at the highest copper exposure.