毒死蜱对斑马鱼胚胎氧化应激效应研究

以斑马鱼为模型,研究了毒死蜱对斑马鱼胚胎形态学的影响,及其对胚胎的氧化应激和氧化损伤作用.将斑马鱼胚胎暴露在梯度浓度的毒死蜱溶液中96h后,发现毒死蜱会造成斑马鱼胚胎严重畸形甚至死亡,其96h半致死浓度为1.18mg/L.对氧化应激相关基因的表达及抗氧化酶活性和丙二醛(MDA)含量进行检测,结果表明,在毒死蜱胁迫下抗氧化酶(SOD、CAT)活性降低,并且其编码基因(Cu/Zn-sod、Mn-sod、cat)的表达受到抑制;但在低浓度毒死蜱胁迫下,抗氧化酶活性并没有受到显著影响,而抗氧化酶基因的表达对毒死蜱更加敏感.毒死蜱能引起gstp2的表达上调,但GST活性与gstp2的表达变化并不一致.处理组胚胎中nrf2表达上调,从而上调抗氧化蛋白和II相解毒酶基因的表达.毒死蜱胁迫下,基因ucp2、cox1表达下调,能够减少呼吸链ROS的产生.同时基因bcl2表达下调,表明凋亡的平衡受到破坏.毒死蜱处理组中MDA含量显著升高,说明毒死蜱能造成斑马鱼胚胎氧化损伤.

Oxidative stress effects of chlorpyrifos on zebrafish embryos

We elucidated the effects of chlorpyrifos exposure on the morphology, oxidative stress and oxidative damage in zebrafish (Danio rerio) embryos. After exposed to concentration gradient of chlorpyrifos solution for 96hours, the rates of deformities and death were dramatically higher than those in the control groups, and the median lethal concentration of CPF was calculated to be 1.18mg/L after a 96h exposure. The expression levels of oxidative stress-related genes, antioxidant enzyme activities and malondialdehyde (MDA) content were investigated. In CPF treatment groups, the antioxidant enzyme (SOD, CAT) activities and the expression levels of their encoding genes (Cu/Zn-sod, Mn-sod, cat) significantly decreased, compared with the control groups. At low concentrations of chlorpyrifos, antioxidant enzyme activities were not affected significantly, while the expression levels of their encoding genes were more sensitive to chlorpyrifos. Chlorpyrifos could induce the expression of nrf2, which played an important role in increased expression of a group of genes encoding antioxidant and phaseⅡdetoxification enzymes, but the kinetics of GST and gstp2 were not consistent with each other. The down-regulation of expression levels of ucp2 and cox1 made contributions to reducing ROS generated by the respiratory chain in CPF treatment groups. Meanwhile, in CPF treatment groups, the expression level of bcl2 was significantly down-regulated, suggesting that the balance of apoptosis was destroyed. MDA content was significantly higher in CPF treatment groups than that in control, indicating that chlorpyrifos could cause oxidative damage in zebrafish embryos.