College of Life Sciences, Henan Normal University, Xinxiang 453007, PR China.
Aquat Toxicol. 2012 Sep 15;120-121:119-25. doi: 10.1016/j.aquatox.2012.05.005. Epub 2012 May 22.
This study assessed the impact of mercury exposure on goldfish (Carassius auratus) embryos based on the dynamic characteristics of chemical parameters. Day-old embryos were exposed to different Hg(2+) concentrations (0, 0.2, 1, 5, and 10 μg/L). Subsequently, the embryos were sampled every 24 h during embryonic development to measure acid phosphatase (ACP), alkaline phosphatase (AKP), lysozyme (LSZ), and catalase (CAT) activities, as well as malondialdehyde (MDA) content. The results revealed that the responses of ACP and AKP to mercury exposure presented in dose-dependent and time-dependent manners. The enzyme activities were significantly induced with increased concentrations and extended exposure (at 5 μg/L after 72 h and 10 μg/L after 48 h; p<0.05 or p<0.01). LSZ was not sensitive to lower Hg(2+) concentrations, whereas LSZ significantly increased at higher concentrations and longer exposure (at 5 μg/L at 120 h and 10 μg/L after 72 h; p<0.05 or p<0.01). CAT activities were significantly inhibited at different periods of embryonic development, particularly at 5 and 10 μg/L (p<0.05 or p<0.01). Reduced CAT activities were observed at 72, 96, and 120 h at 1 μg/L (p<0.05 or p<0.01), whereas a decline at 0.2 μg/L was evident at 96 h (p<0.01). MDA content significantly increased at various stages of embryonic development, particularly at 10 μg/L (p<0.05 or p<0.01), and increased further at 72, 96, and 120 h at 5 μg/L (p<0.05 or p<0.01). At 96 h, MDA content was only increased by exposure to 0.2 and 1 μg/L (p<0.01). The activities of ACP, AKP, and LSZ remarkably increased at 120 h in contrast to 96 h (p<0.05 or p<0.01). Therefore, 96 h is an important shifting period of embryonic development because the activity of enzyme has been enhanced at this time. Thus, the increased ACP, AKP, and LSZ activities revealed an enhanced ability of the embryo to synthesize more enzymes and attenuate mercury damage. CAT activity negatively correlates with MDA accumulation. The enhanced enzyme activities after specific embryonic stages are used to strengthen the ability to cope with mercury stress and attenuate mercury damage. The biochemical parameters, except LSZ, exhibited sensitivity to mercury, suggesting that they may act as potential biomarkers in assessing the environmental mercury risk on C. auratus embryos.
本研究基于化学参数的动态特征，评估了汞暴露对金鱼（Carassius auratus）胚胎的影响。将 1 日龄胚胎暴露于不同浓度的 Hg(2+)（0、0.2、1、5 和 10 μg/L）中。随后，在胚胎发育的每个 24 小时期间对胚胎进行采样，以测量酸性磷酸酶（ACP）、碱性磷酸酶（AKP）、溶菌酶（LSZ）和过氧化氢酶（CAT）的活性以及丙二醛（MDA）含量。结果表明，ACP 和 AKP 对汞暴露的反应呈剂量和时间依赖性。随着浓度的增加和暴露时间的延长，酶活性显著升高（5 μg/L 时 72 小时，10 μg/L 时 48 小时；p<0.05 或 p<0.01）。LSZ 对较低浓度的 Hg(2+)不敏感，而在较高浓度和较长暴露时间下，LSZ 显著增加（5 μg/L 时 120 小时，10 μg/L 时 72 小时；p<0.05 或 p<0.01）。CAT 活性在胚胎发育的不同时期受到显著抑制，特别是在 5 和 10 μg/L 时（p<0.05 或 p<0.01）。在 1 μg/L 时，72、96 和 120 小时时观察到 CAT 活性降低（p<0.05 或 p<0.01），而在 0.2 μg/L 时 96 小时时活性下降明显（p<0.01）。MDA 含量在胚胎发育的各个阶段均显著增加，特别是在 10 μg/L 时（p<0.05 或 p<0.01），而在 5 μg/L 时，72、96 和 120 小时时进一步增加（p<0.05 或 p<0.01）。在 96 小时时，仅在暴露于 0.2 和 1 μg/L 时观察到 MDA 含量增加（p<0.01）。ACP、AKP 和 LSZ 的活性在 120 小时时与 96 小时相比显著增加（p<0.05 或 p<0.01）。因此，96 小时是胚胎发育的重要转变期，因为此时酶的活性已增强。因此，ACP、AKP 和 LSZ 活性的增强表明胚胎增强了合成更多酶的能力，并减轻了汞的损害。CAT 活性与 MDA 积累呈负相关。特定胚胎阶段后增强的酶活性用于增强应对汞应激和减轻汞损害的能力。除 LSZ 外，其他生化参数对汞均敏感，提示它们可能作为评估金鱼胚胎环境汞风险的潜在生物标志物。
