Guo Rui, Zhang Wenya, Ai Shiwei, Ren Liang, Zhang Yingmei
Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, 730000, Lanzhou, People's Republic of China.
Environ Monit Assess. 2017 Jun;189(6):293. doi: 10.1007/s10661-017-5991-6. Epub 2017 May 26.
Oxidative stress (OS) and fluctuating asymmetry (FA) as risk markers for environmental stress are widely used to predict changes in the health and fitness of many animals exposed to pollutants. However, from the perspective of protecting declining amphibians, it remains to be verified which one would be a reliable indicator for amphibians exposed to long-term heavy metal pollution under natural conditions. In this study, the OS and FA of Bufo raddei exposed to natural heavy metal pollution were analyzed to determine which marker is more accurate for indicating heavy metal-induced stress. Three years of data were collected during the breeding season of B. raddei from Baiyin (BY), which has been mainly contaminated with Cu, Zn, Pb, and Cd compounds for a long period, and from Liujiaxia (LJX), which is a relatively unpolluted area. Unexpectedly, although significant accumulation of the four heavy metals was found in the kidney and liver of B. raddei from BY, the levels of superoxide dismutase, glutathione peroxidase, and malondialdehyde in these two organs were found to be irregular, with low repeatability in both BY and LJX. However, significant differences in the levels of FA were observed in B. raddei populations from these two areas over the past 3 years (P < 0.01). The degrees of FA in B. raddei populations from BY and LJX were assessed as degree 4 and 1, respectively. In short, this study suggested that FA was a more reliable and effective indicator than OS to monitor and predict long-term environmental stress on anuran amphibians.
氧化应激（OS）和波动不对称性（FA）作为环境应激的风险标志物，被广泛用于预测许多接触污染物动物的健康和适应性变化。然而，从保护数量减少的两栖动物的角度来看，在自然条件下，对于接触长期重金属污染的两栖动物而言，哪一个会是可靠指标仍有待验证。在本研究中，分析了暴露于自然重金属污染下的中华大蟾蜍的氧化应激和波动不对称性，以确定哪个标志物在指示重金属诱导的应激方面更准确。在中华大蟾蜍繁殖季节，从长期主要受铜、锌、铅和镉化合物污染的白银（BY）以及相对未受污染的刘家峡（LJX）收集了三年的数据。出乎意料的是，尽管在来自BY的中华大蟾蜍的肾脏和肝脏中发现了四种重金属的显著积累，但在这两个器官中，超氧化物歧化酶、谷胱甘肽过氧化物酶和丙二醛的水平却不规则，在BY和LJX两地的重复性都很低。然而，在过去三年中，这两个地区的中华大蟾蜍种群的波动不对称性水平存在显著差异（P < 0.01）。来自BY和LJX的中华大蟾蜍种群的波动不对称程度分别被评估为4级和1级。简而言之，本研究表明，波动不对称性是比氧化应激更可靠、更有效的指标，可用于监测和预测无尾两栖动物面临的长期环境应激。
