溴氰菊酯对克氏原螯虾的氧化胁迫效应

Oxidative stress of deltamethrin to the liver of crayfish (Procambarus clarkii)

为了解溴氰菊酯对克氏原螯虾的毒性及致毒机理,采用24h换水式生物试验研究了溴氰菊酯对克氏原螯虾的96h急性毒性,分光光度法检测了6、12、24和48h后0.01、0.02和0.04μg/L溴氰菊酯对肝胰腺超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活力和丙二醛(MDA)的含量等氧化胁迫相关指标的影响。结果表明,24、48和96h的半致死浓度分别为0.1560、0.0993和0.0562μg/L,安全浓度为5.62ng/L;在整个暴露过程中,溴氰菊酯各个处理组都引起了氧化胁迫相关指标的变化。SOD和CAT活力的变化趋势相同,都呈抑制-诱导-抑制的变化规律,MDA含量则一直高于对照组。暴露6h后,0.01μg/L浓度组MDA含量极显著高于对照组(P<0.01),0.04μg/L浓度组MDA含量约为对照组的1.98倍(P<0.05);暴露12h后,MDA仍保持较高水平,0.02μg/L浓度组MDA含量约为对照组的1.76倍(P<0.05);暴露24h后,各浓度组CAT活力分别比对照组上升了70.98%、73.05%和66.67%(P<0.01);暴露48h后,0.01、0.02μg/L浓度组的SOD活力分别下降了60.38%和45.60%(P<0.01);各指标变化没有明显的剂量相关效应。结果提示,溴氰菊酯对克氏原螯虾毒性极强,在48h内可以通过氧化损伤途径对机体产生毒性作用。鉴于对溴氰菊酯的高度敏感特点,克氏原螯虾也可以被用作水环境中菊酯类农药污染有效的指示生物。

Deltamethrin （ DLM）,one of the regular pyrethroid pesticides,has toxical effects on aquatic animals after entering the natural water due to human activities. As a large-sized crustacean species,crayfish （Procambarus clarkii） is an important link of eco-system of the water. In order to understand the toxical effects and mechanism of DLM on P. clarkii,an acute semi-static toxic test was carried out,and the oxidative stress relative indicators [activities of superoxide dismutase （SOD）,catalase （CAT） and concentrations of malondialdehyde （MDA） in hepatopancreas]were examined at intervals （0,6,12 and 24 h） after being treated with DLM （with the concentration of 0. 01,0. 02 and 0. 04 μg/L） by spectrophotometry. LC50 values of DLM for P. clarkii in 24,48 and 96 h were 0. 156 0,0. 099 3 and 0. 056 2 μg/L,respectively; and its safe concentration was 5. 62 ng/L. In all groups treated with DLM,the oxidative stress relative indicators varied. The activities of SOD and CAT showed the similar variation during the treatments： inhibition-induction- inhibition ,while the levels of MDA were higher in all treated groups than that in the control group. After 6 h treated with DLM,MDA level in the group of 0. 01 μg/L was significantly higher than that in the control group（P 0. 01）,1. 98 times higher in the group of 0. 04 μg/L than that in the control group（P 0. 05）; After 12 h treated with DLM,MDA level was 1. 76 times higher in the group of 0. 02 μg/L than that in the control group（P 0. 05）. The activities of CAT of three treated groups were 70. 98% ,73. 05% and 66. 67% respectively higher than the control group after 24 h DLM treated（P 0. 01）; After 48 h treated with DLM, SOD activities decreased by 60. 38% and 45. 60% in the groups of 0. 01 and 0. 02 μg/L,respectively（P 0. 01）. The three different treated groups did not show apparent dose-dependent effects. The results provide evidences that DLM performed an extremely high toxical effect on P. clarkii and may play its adverse role through an oxidative damage pathway within 48 h. P. clarkii could be used as a bio-indicator to the pyrethroid pesticides pollution in the water as it is highly sensitive to pyrethroids.