Gagné F, Blaise C, Hellou J
St. Lawrence Centre, Research on Aquatic Ecosystems, Environment Canada, 105 McGill, Montréal, Québec, Canada H2Y 2E7.
Comp Biochem Physiol C Toxicol Pharmacol. 2004 May;138(1):33-44. doi: 10.1016/j.cca.2004.04.006.
Freshwater mussels, Elliptio complanata, were caged in special benthic pens and were immersed at one upstream (Ups) site and two downstream sites (8 and 11 km) of a primary-treated municipal effluent plume for 1 year. The levels of metallothionein-like proteins (MT), lipid peroxidation, protein-free DNA strands and glutathione S-transferase (GST) activity were assayed in digestive gland, gill and gonad tissues to evaluate biological effects and damage. The levels of monoamines (serotonin and dopamine) in nerve ganglia, ATP-dependent transport activity and monoamine oxidase (MAO) activity were also investigated in the homogenates, synaptosomes and mitochondria, respectively. Results showed that significant amounts of sediment accumulated in cages and 82% of mussels survived the yearlong exposure period at the downstream sites. MT-like proteins were induced in all tissues with the following response intensity: gill (3-fold), digestive gland (1.4-fold) and gonad tissues (1.3-fold). Lipid peroxidation decreased (2.5-fold) in digestive gland but increased in gill (1.6-fold) and in gonad tissues (1.5-fold). GST activity was readily increased in digestive gland (2.5-fold), suggesting the presence of organic contaminants in the plume. Levels of protein-free DNA strands did not vary significantly in digestive gland and gill tissues but were significantly reduced in gonad tissues (2.5-fold) relative to the upstream site. In visceral nerve ganglia, both serotonin and ATP-dependent serotonin transport decreased 1.7-fold with a 4-fold increase of 5-hydroxyindole acetate (5-HIAA, a serotonin metabolite) level relative to the upstream site. However, MAO activity was somewhat reduced at downstream sites (0.7- to 0.9-fold of the activity at the upstream site). Dopamine levels were found to be decreased (1.5-fold), but dopamine ATP-dependent transport activity was increased 1.8-fold, suggesting reduced dopaminergic activity. These results indicate that estrogenic chemicals are likely at play, and the increased dopamine and decreased serotonin ATP-dependent transport suggest that the municipal plume was serotonergic for mussels located at the downstream sites. Mussels exposed for 1 year display a complex but characteristic pattern of responses that could lead to harmful health effects including neuroendocrine disruption of reproduction.
将淡水贻贝椭圆丽蚌置于特殊的底栖围栏中，在一处上游（Ups）地点以及一处初级处理的城市污水羽流下游两个地点（分别距离排放口8公里和11公里）浸泡1年。对消化腺、鳃和性腺组织中的类金属硫蛋白（MT）水平、脂质过氧化、无蛋白DNA链以及谷胱甘肽S - 转移酶（GST）活性进行测定，以评估生物学效应和损伤情况。还分别对匀浆、突触体和线粒体中的神经节单胺（血清素和多巴胺）水平、ATP依赖性转运活性以及单胺氧化酶（MAO）活性进行了研究。结果显示，笼子里积累了大量沉积物，82%的贻贝在下游地点度过了为期一年的暴露期。所有组织中均诱导产生了类MT蛋白，其响应强度如下：鳃（3倍）、消化腺（1.4倍）和性腺组织（1.3倍）。消化腺中的脂质过氧化作用降低（2.5倍），但鳃（1.6倍）和性腺组织（1.5倍）中的脂质过氧化作用增加。消化腺中的GST活性显著增加（2.5倍），表明污水羽流中存在有机污染物。消化腺和鳃组织中无蛋白DNA链的水平没有显著变化，但相对于上游地点，性腺组织中的无蛋白DNA链水平显著降低（2.5倍）。在内脏神经节中，血清素和ATP依赖性血清素转运均下降了1.7倍，而5 - 羟吲哚乙酸（5 - HIAA，血清素代谢产物）水平相对于上游地点增加了4倍。然而，下游地点的MAO活性有所降低（为上游地点活性的0.7至0.9倍）。发现多巴胺水平下降（1.5倍），但多巴胺ATP依赖性转运活性增加了1.8倍，表明多巴胺能活性降低。这些结果表明可能存在雌激素类化学物质，多巴胺增加以及血清素ATP依赖性转运减少表明城市污水羽流对位于下游地点的贻贝具有血清素能作用。暴露1年的贻贝表现出复杂但具有特征性的反应模式，这可能导致包括生殖神经内分泌紊乱在内的有害健康影响。
