四溴双酚A对赤子爱胜蚓的生长和基因表达的影响

Effects of Tetrabromobisphenol A on Growth and Gene Expression of Earthworms( Eisenia fetida)

试验采用人工土壤法,通过14 d急性毒性试验,研究了不同剂量TBBPA对赤子爱胜蚓(Eisenia fetida)生长、基因表达的影响。在14 d急性毒性试验中,随着暴露时间和浓度的增加,蚯蚓生长受到了显著抑制,未出现死亡现象。超氧化物歧化酶(SOD)的基因表达量在低浓度(50 mg·kg-1)时受到诱导上调;谷胱甘肽转移酶(GST)的基因表达量在400 mg·kg-1染毒组受到明显诱导,是对照组的8.73倍;热休克蛋白(Hsp70)的基因表达量在50、100和200 mg·kg-1染毒组被诱导上调。基因表达量的变化显示,在50、100、200 mg·kg-1浓度条件下,蚯蚓可以利用自身的抗氧化能力维持体内的动态平衡稳定,使得机体免受损伤。但是在超过400 mg·kg-1浓度后,TBBPA的毒性效应超过了机体的应对能力,使机体遭受损伤,外在特征主要表现为蚯蚓身体蜷缩、变细变硬。从生物标志物角度,基因表达量的变化对TBBPA毒性效应的指示作用较生长抑制率更为敏感。

In this study, the acute toxicity of TBBPA on the earthworm Eiseniafetida was assessed by growth inhibition and changes in gene transcript. The growth inhibition rates of all TBBPA dose groups were signifi- cantly higher than those of controls, but no deathwas found. Superoxide dismutase （SOD）gene expression was up-regulated at the concentration of 50 mg· kg-1. Significant up-regulation of glutathione transferase （GST） gene expressionwas only found at the concentrations of 400 mg·kg-1. Earthworms exposedto TBBPA provoked a significant up-regulation of heat shock protein（Hsp70） gene expression levels at the concentrations of 50, 100, 200 mg·kg-1. With the changes of gene expression levels at the concentrations of 50, 100, 200 mg·kg-1, earthworms maintained the stability of dynamic balance, and protected the body from damage by usingthe antioxidant system. However, the toxic effects of TBBPA made the antioxidant system useless over theconcentration of 400 mg＂ kg1, thus made earthwormsthin and stiff. Change in gene expression was more sensi- tive than growth inhibitionrate for indicating the toxic effects of TBBPA.