镧对稀有鮈鲫肝胰脏抗氧化酶活性及MDA含量的影响

Effect of Lanthanum Exposure on the Antioxidase Activity and MDA Content in the Hepatopancreas of Gobiocypris rarus

以氯化镧(LaCl_3·7H_2O)为试验毒物,以稀有鮈鲫(Gobiocypris rarus)为试验材料,采用21 d慢性毒性试验(La^(3+)浓度分别为0.00、0.04、0.08、0.16、0.32、0.80 mg/L),通过检测稀有鮈鲫肝胰脏中超氧物歧化酶(SOD)、过氧化氢酶(CAT)活性和丙二醛(MDA)含量,研究了镧暴露胁迫对水生动物抗氧化系统的影响,以期从抗氧化生理响应的角度探讨稀土元素镧对水生动物的毒理机理。结果显示,与对照组相比,0.04～0.32 mg/L试验组肝胰脏SOD活性出现一定程度降低(P>0.05),但0.80 mg/L组SOD活性出现一定程度上升(P>0.05);0.04～0.32 mg/L试验组肝胰脏CAT活性较对照组出现一定程度降低(P>0.05),但0.80 mg/L组CAT活性出现一定程度上升(P>0.05),且0.80 mg/L组CAT活性显著高于0.04～0.32 mg/L组(P<0.05);0.04～0.16 mg/L试验组肝胰脏MDA含量较对照组出现一定程度降低(P>0.05),0.32 mg/L组MDA含量略微升高(P>0.05),0.80 mg/L组MDA含量显著高于对照组(P<0.05),也显著高于其它La^(3+)暴露组(P<0.05)。研究表明,一定浓度的La^(3+)暴露胁迫会对环境中水生生物抗氧化系统产生不利影响。

The presence of rare earth elements(REE)in surface runoff and wastewater associated with the excavation and smelting of REE threatens aquatic ecosystems.Research on the effects of REE on aquatic organisms is lacking,particularly regarding the toxic effects and toxicological mechanisms.The rare minnow(Gobiocypris rarus)is recommended as a test organism,according to the guidelines for the testing of chemicals(Ministry of Environmental Protection of China).To explore the toxicological mechanism of REE in aquatic animals,we performed a chronic toxicity test to examine the antioxidant response of the rare minnow to different concentrations of lanthanum(La3+).The fish were reared in freshwater and exposed to 0.00,0.04,0.08,0.16,0.32 and 0.80 mg/L La3+for 21 d.The activities of superoxide dismutase(SOD)and catalase(CAT)and the content of malondialdehyde(MDA)in the hepatopancreas of test minnows were analyzed.In the control group,SOD activity in the hepatopancreas was(79.50±19.01)U/mg.SOD activities at the lower La3+exposures(0.04-0.32 mg/L)were lower than in the control group(P>0.05),but at 0.80 mg/L La3+,SOD activity was higher than the control group(84.50±6.31)U/mg(P>0.05).Hepatopancreatic CAT activity in the test minnows displayed a trend similar to SOD activity;lower La3+exposures(0.04-0.32 mg/L)decreased activity(P>0.05),while exposure to 0.80 mg/L La3+increased activity(P>0.05)compared to the control group.CAT activity was significantly higher in the 0.80 mg/L La3+group than in the 0.04-0.32 mg/L La3+groups(P<0.05).MDA content in the control group was(2.51±1.02)nmol/mg,slightly lower in the 0.04-0.16 mg/L La3+groups(P>0.05)and slightly higher in the 0.32 mg/L group(P>0.05).However,MDA content in the 0.80 mg/L La3+group was significantly higher than in the control group and low concentration(0.04-0.32 mg/L)groups(P<0.05).Results indicate that La3+exposure produces a toxic response in the antioxidant system of Gobiocypris rarus and perhaps other aquatic organisms.