摘要
为探讨甲醛、苯、甲苯及二甲苯混合气体急性暴露对小鼠肺脏的氧化损伤作用,选用雄性健康昆明种小鼠50只,随机分为对照组和4个染毒组。染毒组1到4中甲醛、苯、甲苯和二甲苯浓度依次为:1.0+1.1+2.0+2.0μg·L-1、3.0+3.3+6.0+6.0μg·L-1、5.0+5.5+10.0+10.0μg·L-1、10.0+11.0+20.0+20.0μg·L-1,各染毒组混合气体的浓度分别是我国室内空气质量标准(GB/T18883-2002)的10、30、50和100倍。用静式吸入染毒方式,每天染毒2h,共染毒10d,实验结束后,测定小鼠肺脏中的氧化损伤指标。结果表明:染毒组小鼠的体重增加幅度均低于对照组,肝脏和脾脏系数显著低于对照组,肺脏ROS、MDA含量随染毒剂量的增加而增加,T-AOC、GSH、CAT、GSH-Px及SOD活力随染毒剂量的增加而降低,并且ROS、MDA含量与混合气体的浓度呈显著的正相关关系,GSH含量与混合气体的浓度呈显著的负相关关系。研究结果显示,甲醛、苯、甲苯及二甲苯混合气体急性暴露对小鼠肺脏具有氧化损伤作用,混合气体的联合毒性效应强于单一组分,ROS、MDA和GSH可以作为评价VOCs急性暴露对机体氧化损伤作用的敏感生物学标志。
Cytotoxicity effects and mechanism of 20 nm nano-Fe0 on Escherichia coli were studied. In this paper, morphology of E. coli in the presence of nano-Fe0 was observed by transmission electron microscopy （TEM）. E.coli cells were exposed to 0, 112, 560, 1 120 mg·L-1 nano-Fe0 particles. Experiments were carried out to study the inhibitive effect of nano-Fe0 on E.coli growth. E. coli exposed to nano-Fe0 for 24 h, the activities of lactate dehydrogenase （LDH）, cellular superoxide dismutase （SOD）, malondialdehyde （MDA） were determined. Moreover, the influence of addition of N-Acetylcysteine （NAC） on the viability of cells was studied. TEM images of E.coli cells treated with nano-Fe0 exhibited significant disruption of the cell membranes. Experimental results of growth curves showed that nano-Fe0 nanoparticles could inhibit the growth of cells in liquid LB medium. Additionally, the shortened log phase and the prolonged stable phase of E.coli both resulted from the toxicity of nano-Fe0. Furthermore, the stable phase of E.coli is proportional to the concentration of nano-Fe0 particles. The activities of LDH and the levels of MDA significantly increased and there was a linear relationship between the concentration of nano-Fe0 and MDA levels, while the activities of SOD significantly decreased. To nano-Fe0-NAC exposure groups, the number of cell was higher than that of simple nano-Fe0 exposure groups. The results demonstrated that oxidative damage was the mechanism of nano-Fe0 toxicity to E. coli.
出处
《生态毒理学报》
CAS
CSCD
北大核心
2012年第1期87-92,共6页
Asian Journal of Ecotoxicology
基金
国家高技术研究发展计划(863)项目(No.2010AA064904)
关键词
甲醛
苯系物
氧化损伤
生物学标志
nano-Fe0
Escherichia coli
growth curves
enzymes activities
oxidative damage
