汞和硒对剑尾鱼Na^+/K^+-ATPase活性的影响

Effects of Mercury and Selenium on Na ^+/K ^+-ATPase Activity in Xiphophorus helleri Heckel

应用浸浴法研究汞(Hg)对剑尾鱼(XiphophorushelleriHeckel)鳃和肝脏Na+/K+ATPase活性的影响以及硒(Se)对机体Na+/K+ATPase汞中毒的保护作用.结果表明,Hg和Se对剑尾鱼96hLC50分别为0.84mg/L和6.64mg/L.Hg对剑尾鱼鳃和肝脏Na+/K+ATPase活性的影响相似,与对照组相比,处理d1时低浓度Hg组鳃和肝脏ATPase活性没有明显变化(P>0.05),但高浓度Hg组ATPase活性变化显著(P<0.05),至d3和d5时,酶活性均极显著下降(P<0.01),鱼鳃和肝脏酶活性分别下降32%和60%,表明Hg处理对鳃和肝脏Na+/K+ATPase活性具有抑制作用.单独加Se组鱼鳃和肝脏Na+/K+ATPase活性在d3和d5显著提高(P<0.01).Hg+Se组与Hg组相比,酶活性有明显差异(P<0.05或P<0.01),Se对剑尾鱼Hg中毒具有保护作用.剑尾鱼鳃和肝细胞Na+/K+ATPase活性可作为对水环境汞污染效应环境风险评价(ERA)的有效生物学标记.

The effects of mercury （Hg） and selenium （Se） on the Na ^＋/K ^＋ -ATPase activity in gill and liver tissues, and the antagonistic effect of Se on gill and liver damages of swordtail （ Xiphophorus heUeri Heckel ） initiated by Hg were investigated with addictive index method. The results showed that the semi - lethal concentrations （ LC50 ） of 96 h for Hg and Se to swordtails were 0. 84 mg/L and 6.64 mg/L, respectively, The effects of Hg on the Na ^＋/K ^＋ -ATPase activity in the gill and liver tissues were similar. The activities of Na ^＋/K ^＋ -ATPase in gill and liver tissues did not make any obvious changes at low Hg concentrations on d 1 （ P 〉 0.05 ）. Nevertheless, the activities of Na ^＋/K ^＋ -ATPase were influenced remarkably （ P 〈 0.05 ） at high Hg concentrations in contrast to the control group. However, low and high Hg concentrations could remarkably （ P 〈 0.01 ） decrease the activities of Na ^＋/K^＋ -ATPase in gill and liver by 32% and 60% compared with the control group on d 5, which indicated that Hg could inhibit the activities of Na ^＋/K^＋ -ATPase in gill and liver. The Na ^＋/K^＋ -ATPase activities in gill and liver were significantly increased （ P 〈 0.01 ） when swordtails were exposed to Se after d 3 and d 5. Compared to the single Hg^2 ＋ treatment, the mixed Se^4 ＋ Hg^2 ＋ exposure could significantly （ P 〈 0.05 and P 〈 0.01 ） restrain the fall of the activity of Na ^＋/K^＋-ATPase in gill and liver tissues during the experimental period, which suggested that Se could be used to protect the fish from poisoning by Hg. In addition, the gill and hepatic Na ^＋/K ^＋-ATPase activity in swordtails could be considered a valid biomarker for environmental risk assessment （ERA）. Tab 2, Ref 16