Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong.
Environ Sci Pollut Res Int. 2012 Nov;19(9):3831-9. doi: 10.1007/s11356-012-1032-8. Epub 2012 Jun 20.
The aim of this study was to demonstrate that zebrafish embryos subjected to a priming exposure provided by one environmental stressor (low-dose alpha particles) can induce an adaptive response against a subsequent challenging exposure provided by another environmental stressor (heavy metal Cd). The effect thus identified would be an antagonistic multiple stressor effect. The effects of alpha particle radiation and/or Cd on whole embryos were studied through quantification of apoptotic signals at 24 h post-fertilization (hpf). Embryos were stained with the vital dye acridine orange, followed by counting the stained cells. For each set of experiments, 30 dechorionated embryos were divided into three groups, each having ten embryos. The three groups of embryos were referred to as (A) the control group, which received no more further treatments after dechorionation, (B) Cd-treated group, which did not receive any priming exposure and would receive a challenging exposure at 10 hpf and (C) (alpha + Cd)-treated group, which would receive both priming and challenging exposures. We defined the normalized net number of apoptotic signals in the (alpha + Cd)-treated group as N (C) * = [(apoptotic signals for (alpha + Cd)-treated group - average apoptotic signals for the corresponding control group)/average apoptotic signals for the corresponding control group] and that in the Cd-treated group as N (B)* = [(apoptotic signals for Cd-treated group - average apoptotic signals for the corresponding control group)/ average apoptotic signals for the corresponding control group]. By using the non-parametric Mann-Whitney U statistic, we were able to show that N (C) * was significantly smaller than N (B) *(p = 0.006). These demonstrated an antagonistic multiple stressor effect between ionizing radiation and Cd through the induction of an adaptive response by the ionizing radiation against subsequent exposures to Cd.
本研究旨在证明，斑马鱼胚胎在受到一种环境胁迫（低剂量 α 粒子）的预暴露后，可以对随后的另一种环境胁迫（重金属 Cd）的挑战性暴露产生适应性反应。这种被识别出的效应将是一种拮抗的多重胁迫效应。通过在受精后 24 小时（hpf）量化凋亡信号，研究了 α 粒子辐射和/或 Cd 对整个胚胎的影响。胚胎用吖啶橙活染，然后计数染色细胞。对于每组实验，30 个去壳胚胎被分为三组，每组 10 个胚胎。三组胚胎分别称为 (A) 对照组，去壳后不再接受进一步处理，(B) Cd 处理组，未进行任何预暴露，在 10 hpf 时将接受挑战性暴露，(C) (α + Cd)-处理组，将同时接受预暴露和挑战性暴露。我们将 (α + Cd)-处理组的归一化净凋亡信号数定义为 N(C)* = [(α + Cd)-处理组的凋亡信号 - 相应对照组的平均凋亡信号）/相应对照组的平均凋亡信号]，Cd 处理组的定义为 N(B)* = [(Cd 处理组的凋亡信号 - 相应对照组的平均凋亡信号）/相应对照组的平均凋亡信号]。通过使用非参数 Mann-Whitney U 统计，我们能够证明 N(C)显著小于 N(B)(p=0.006)。这表明通过电离辐射诱导的适应性反应与随后暴露于 Cd 之间存在电离辐射和 Cd 之间的拮抗多重胁迫效应。
