六溴环十二烷对发育期大鼠脑单胺类神经递质质量比及单胺氧化酶活性的影响

通过研究发育期大鼠脑单胺类神经递质质量比及单胺氧化酶活性,探讨环境暴露水平的六溴环十二烷对发育期大鼠的神经毒性作用。选择10μg/kg、50μg/kg、100μg/kg、300μg/kg的剂量对新生3 d大鼠进行暴露,饲养42 d后断头取脑组织,测定多巴胺(DA)、去甲肾上腺素(NE)、5-羟色胺(5-HT)的质量比及单胺氧化酶(MAO)的活性。结果表明,在10~100μg/kg的暴露剂量范围,DA质量比随暴露剂量的升高而下降,NE质量比呈现上升趋势,5-HT质量比则极显著性升高(p<0.01);与此同时,MAO的活性随剂量增加而升高,在100μg/kg剂量出现显著性升高(p<0.05)。而300μg/kg的剂量作为较高暴露水平的参照,只对DA产生显著性影响(p<0.05)。DA、5-HT、NE的质量比及MAO活性的变化可能在大鼠的中枢神经系统的发育障碍中发挥了重要作用,并且环境暴露水平的HBCD对发育期大鼠脑具有低剂量高效应的毒性反应特征。

Effects of hexabromocyclododecane(HBCD) on monoamine neurotransmitters contents and monoamine oxidase activity of developmental rat brain

The paper is aimed to study the hexabromocyclododecane(HBCD) as a kind of brominated flame retardants extensively used in the industrial production.The spectrophotometry and enzyme-linked immunosorbent assay(ELISA) can be used for examining the contents of dopamine(DA),noradrenalin(NE),5-hydroxytryptamine(5-HT) and monoamine oxidase(MAO) activity when the sprague-dawley 3-day old rats were exposed to the different dosages(10 μg/kg,50 μg/kg,100 μg/kg,300 μg/kg body weight) of HBCD in a period of 42 days.The results of our experiments with the rats show that,compared with the controlled group,DA contents of 10 μg/kg and 300 μg/kg exposures tends to drop significantly(p<0.05),in a decreasing rate in a range of 10-100 μg/kg exposure doses.However,no significant changes were detected of NE.In addition,an increase trend can be found in the range of 10 μg/kg to 100 μg/kg doses,with the 5-HT contents of 10-100 μg/kg exposures increased significantly(p<0.01).As for the monoamine oxidase,an increase trend can be found with MAO activity in the range of 10 to 100 μg/kg doses and significantly changed at the dose of 100 μg/kg(p<0.05).When the dose is kept at a level of 300 μg/kg,the trend is likely to drop,though not enough significantly. DA,NE and 5-HT were found to play a important role in the learning,memory and moods in the rats’ brain.Changing the contents of DA,5-HT,disorders can be found with the central nervous system with the rats when the developmental HBCD was exposed to the NE and MAO activities.Compared with the dose of 300 μg/kg, severe effects were detected on the neurotransmitters and MAO at a level of 10100 μg/kg.It indicates that HBCD has the feature of low-dosage and high toxicity to the developmental rat brain.Furthermore,the exposure dosages of 10-100 μg/kg can only produce a mirror effect in comparison with the content of HBCD in the real environment.However,HBCD of the environmental exposure levels proves to produce neurotoxicity and have effect on the learning and memory system of the developmental rats.Thus,it can be said that this paper has provided an important reference in the study of the HBCD exposure and its effect on the public health in the environment,especially on children’s healthy growth.