硒对汞致剑尾鱼肝氧化损伤的拮抗作用

Antagonistic effect of selenium on oxidative damage of liver in swordtail (Xiphophorus helleri Heckel) initiated by mercury

在实验条件下 ,应用浸浴法研究了汞 ( Mercury,Hg)对剑尾鱼 ( Xiphophorushelleri Heckel)肝组织的抗氧化功能的影响以及硒( Selenium,Se)对汞损伤的保护作用。结果表明 :在低质量浓度 Hg组和中等质量浓度 Hg组的前期 ,肝组织的超氧化物歧化酶 ( Superoxidedismutase,SOD)和谷胱甘肽过氧化物酶 ( Glutathione peroxidase,GSH-Px)的活性都受到不同程度的诱导 ,在中等质量浓度暴露第 3天上述指标诱导值达到高峰 ,与对照组比较差异显著 ( P <0 .0 5 ) ;而高质量浓度 Hg组使这两种酶活性显著下降 ,其中 ,SOD和 GSH-Px的活性在最低时分别为对照组的 68%和 3 8.2 % ,差异极显著 ( P <0 .0 1)。丙二醛 ( melonedialdehyde,MDA)含量在整个染毒过程中一直升高 ,与对照组相比 ,差异显著 ( P <0 .0 5 )。 Hg加 Se组与 Hg组相比 ,SOD和 GSH-Px活性都有很大程度提高 ,MDA含量也有所下降 ,表明 Se对 Hg致剑尾鱼肝氧化性损伤有明显保护作用 ;但相对高 Se组其保护性不明显 ,说明其对机体的保护作用受用量的严格限制。实验结果还表明 ,GSH-Px可以考虑作为

The present article aims to present the authors' research on the effect of mercury on the superoxide dismutase(SOD) and glutathione peroxidase(GSH-Px) activities and the concentration of melonedialdehyde (MDA) in liver tissue of swordtail(Xiphophorus helleri Heckel). Our research results indicate that the activities of SOD and GSH-Px were induced by mercury at low concentrations during early stage, and the induction reached to a significant level on the third day in contrast to the control group. However, the high concentration Hg can remarkably decrease the activities of SOD and GSH-Px to 68% and 38.2% of the control group. Nevertheless, the concentration of MDA was able to maintain significant increase all through the exposure period. Another result shows that Se could remarkably prevent the decrease of SOD and GSH-Px in the liver, as well as make the concentration of MDA decrease, particularly compared with the contrast Hg group. However, it is beyond expectation that the Ⅳ group ((0.105Hg +0.064Se) mg/L) reveals little protections, therefore, it is suggested that the dose of Se used for protection from the poisoning of Hg should be considered. In addition, the activity of GSH-Px is also recommended as a biomarker for indicating the oxidative damage to the liver of swordtail fish.