【作者】 朱丽娜；

【导师】 张迎梅；

【作者基本信息】 兰州大学 ， 动物学， 2007， 硕士

【摘要】 五氯酚(Pentachlorophenol，PCP)是一种广谱杀虫剂，用途广，用量大，已经成为环境中的一种主要污染物。国内外关于PCP污染对生物的毒性效应研究很多，对PCP的遗传毒性也已做过广泛的研究，但从研究结果来看矛盾较多，对PCP的遗传毒性作用尚未获得最终结论，而且对常见的湿地环境污染指示生物——两栖类的遗传毒性作用研究甚少。因此，本文选择我国北方地区广布种——花背蟾蜍(Bufo raddei)为实验材料，以PCP为染毒物，进行体内注射急性毒性实验，体内剂量分别为0.0、12.5、25.0mg/Kg PCP，且设一丙酮阳性对照，分别于染毒3、24和48h后，研究PCP对B. raddei血细胞微核及核异常的影响；对肝、肾的DNA损伤作用和酶活性的影响。同时用高效液相色谱检测染毒后PCP在B. raddei肝、肾中的残留量，从而更合理有效地探讨PCP的生物毒性机理，并为水环境中该类化合物污染影响的早期预报和防治提供参考依据。通过对B. raddei血细胞微核及核异常情况的测定，结果表明：核异常率处理组与空白及对照组相比具有显著差异(P＜0.01)，且随处理浓度增大而增大，随处理时间延长先上升后降低。雄性B. raddei微核率变化与核异常率呈现一致趋势，雌性B. raddei微核率变化趋势不明显。总体来说，处理组核异常率及微核率明显高于空白与对照，但雌雄之间差异不显著(P＞0.05)。DNA损伤测定结果表明：PCP明显诱导了B. raddei肝、肾细胞DNA损伤。处理组肝细胞DNA损伤率及损伤程度均明显高于对照组(P＜0.01)；雌、雄肝细胞的DNA损伤率及雌性肝细胞DNA损伤程度随时间变化先升高后降低；雄性B. raddei肾细胞DNA损伤率及损伤程度均略高于雌性。B. raddei肝细胞DNA损伤率及损伤程度都高于肾细胞。对不同处理时间B. raddei肝脏和肾脏的谷胱甘肽转移酶(Glutathione Transferases, GST)活性测定结果显示：雄性肝脏中GST活性在染毒3h后受到明显的诱导，活性增高，随着处理时间的延长，活性降低趋于平缓；雌性肝脏的GST活性实验过程中变化不明显。肾脏中的GST酶活性雌雄变化趋势基本一致，都是随时间先降低再升高。对不同处理时间B. raddei肝脏和肾脏的乳酸脱氢酶(Lactate Dehydrogemase, LDH)活性测定结果，未发现有规律性变化。PCP处理组的研究结果表明，少量的PCP已经对两栖类有严重的毒害。综合考虑，应禁止PCP在大田使用，建议对我国现行废水排放标准进行综合考虑和调整。更多还原

【Abstract】 Pentachlorophenol (PCP), as a wide spectrum pesticide has been used widely, has become a major pollutant to the environment. Many studies have reported that the effects of PCP on organisms and the genetic effects in organisms. Yet these results are contradictory and no final conclusion has been reached on the genetic toxicity of PCP. Amphibians have been accepted as the indicator of the environmental pollution and employed to investigate the effects of various pollutants on organisms and the environment. However, few studies have been performed to observe the genetic toxicity effects inflicted on amphibians by PCP, especially the PCP intoxication. Bufo raddei is a widely distributed species in the north of China. The experimental toads were treated by PCP through endermic injection at a dose of 0.0,12.5,25.0 mg/Kg once time (acet is control) and were sacrificed at the end of 3 ,12 and 48 hours after once treatment. The effects of PCP on the micronucleus and nucleus abnormity in the blood cells and DNA damage and enzyme activity of livers and kidneys were observed and detected. Additionally, the high performance liquid chromatography (HPLC) was utilized to determine the quantity of the residual PCP within the livers and kidneys of B. raddei and provide proposals for the early prevention and control of PCP in the water.The results indicated that the ratio of abnormal nuclei after treatment with PCP was higher and significantly different from the control (P<0.01), which increased with the increase in the PCP concentration, and increased initially and then decreased with the protraction of the treatment time. For the female B. raddei, the variation in the ratio of both micronuclei and abnormal nuclei exhibited the same tendency, while the variation of the ratio of micronuclei within the male was indistinguishable. In all, the treatment of PCP exerted significant influences on the ratio of micronuclei and abnormal nuclei in female and male B. raddei and no difference between the female and the male was observed(P>0.05).Besides, the results also showed that PCP significantly induced the DNA damage of the liver cells and had great genetic toxicity on B. raddei. The result showed that the percentage and extent of DNA damage after treatment with PCP were significantly higher compared with control (P<0.01); The percentage of DNA damage of the liver cells in male and female B. raddei increased initially and then decreased with the protraction of the treatment time, so did the extent of DNA damage of the liver cells in female B. raddei. The percentage and extent of DNA damage of liver cells were higher compared with kidney cells.The liver and kidney of B. raddei was also designated to study the effects of PCP on the activity of Glutathione Transferase (GST) and Lactate Dehydrogenase (LDH). The results showed that the GST activity within the liver of the male was apparently induced 3 hours after the intoxication of B. raddei and began to deduce and finally kept stable with the elongation of the treatment time, whilst the GST activity didn’t exhibit significant variation throughout the treatment within the treated female B. raddei. Furthermore, both PCP-injected male and female body of B. raddei showed the similar variation in the GST activity, which decreased firstly and then rose with the prolongation of time. However, the variation tendency of the activity of LDH within treated male and female B. raddei was not clearly observed.The experimental findings from the treatment with low concentrations of PCP were that a small quantity of PCP brought serious toxicity to amphibians. All things considered, the application of PCP into the crop fields must be absolutely banned and the successful establishment of the sewage discharge standard can be preceded by comprehensive considerations.更多还原