铈对镉染毒泥鳅肝脏中丙二醛含量和脱氧核糖核酸损伤的影响

Joint Effect of Cerium on MDA Content and DNA Damage Incused by Cadmium in Loach Liver

目的研究稀土元素铈对镉暴露泥鳅肝脏中丙二醛(MDA)含量和脱氧核糖核酸损伤的影响。方法将泥鳅随机分为空白对照组、低(0.025 mg/L)、中(0.25 mg/L)、高(2.5 mg/L)剂量 Cd^(2+)染毒组、低(0.025 mg/L Cd^(2+)+0.025 mg/L Ce^(3+))、中(0 25 mg/L Cd^(2+)+0.25 mg/L Ce^(3+))、高(2.5 mg/L Cd^(2+)+2.5 mg/L Ce^(3+))剂量联合染毒组,每组60条。分别于第1、2、3、5、7、10天采用硫代巴比妥酸法测定泥鳅肝脏中的 MDA 含量,于染毒后第7天采用琼脂糖凝胶电泳对泥鳅肝脏中 DNA 的完整性进行分析。结果第1、2天低剂量 Cd^(2+)染毒组 MDA 含量高于对照组,差异有统计学意义(P<0.05);中、高剂量 Cd^(2+)染毒组短时间内(前3天)MDA 含量低于对照组,从第5天开始,MDA 含量开始升高。低剂量联合染毒组的 MDA 含量短时间内(前3天)低于对照组,差异有统计学意义(P<0.01);随着时间的延长(第5、7、10天),差异无统计学意义(P>0.05);与对照组相比,第1、2天中剂量联合染毒组 MDA 含量较低,第5、7、10天 MDA 含量较高,差异均有统计学意义(P<0.05或 P<0.01);而高剂量联合染毒组 MDA 含量均高于对照组。DNA 在 Cd^(2+)单一胁迫下遭到不同程度地损伤,加 Ce^(3+)处理后,低、中剂量组 DNA 损伤得到恢复,高剂量组则损伤加重。结论 Cd^(2+)可增加肝脏中 MDA 含量,对脱氧核糖核酸有损伤作用。低浓度的 Ce^(3+)对 Cd^(2+)造成的损伤有缓解作用,高浓度的 Ce^(3+)对 Cd^(2+)造成的损伤有加重作用。

Objective To study the protective effect of cerium on changes of MDA content and DNA damage induced by cadmium in loach liver. Methods The loaches were randomly divided into control group and low （0.025 mg/L）, moderate （0.25 mg/L）, high（ 2.5 mg/L）Cd^2＋ exposed group and low（0.025 mg/L Cd^2＋ ＋0.025 Ce^3＋）, moderate（ 0.25 mg/L Cd^2＋＋0.25 mg/L Ce^3＋）, high （2.5 mg/L Cd^2＋ ＋2.5 mg/L Ce^3＋）Cd^2＋ ＋Ce^3＋ exposed group, the MDA content in loach liver was determined at 1d, 2d, 3d, 5d, 7d and 10 d of exposure with the method of TBA, the MDA damage in loach liver was detected at 7 d with the method of agarose gel eleetrophoresis. Results The MDA content of low Cd^2＋ exposed group was higher than that in the control at 1d and 2 d （P〈0.05）, the MDA contents of low,moderate Cd^2＋ exposed group were higher than those in the control in short time （before 3 days）,and began to increase from 5 d. The MDA content of low Cd^2＋ ＋Ce^3＋ exposed group was lower compared with the control （P〈0.05） in short time （before 3 days）,but the difference was not significant as the time prolonged （the 5 d,7 d）,the MDA content of moderate Cd^2＋ ＋Ce^3＋ exposed group was lower at 1 d,2 d, while higher at 5 d,7 d, 10 d,showed a significant difference compared with the control, the MDA content of high Cd^2＋ ＋Ce^3＋ exposed group was higher than that in the control. The DNA was damaged in degrees induced by single cadmium exposure,after joined cerium,the damage of low and moderate Cd^2＋ ＋Ce^3＋ exposed group were recovered, while the high Cd^2＋＋Ce^3＋ exposed group got worse. Conclusion Cerium of low concentration may have an antagonistic joint effect on the damage induced by cadmium, but at high concentration, it will show a synergistic joint effect.