Akvaplan-NIVA AS, Fram center, 9296 Tromsø, Norway.
Comp Biochem Physiol C Toxicol Pharmacol. 2011 Jun;154(1):28-35. doi: 10.1016/j.cbpc.2011.02.008. Epub 2011 Mar 3.
The efficiency of antioxidant defenses and relationship with body burden of metal and organic contaminants has not been previously investigated in arctic seabirds, neither in chicks nor in adults. The objective of this study was to compare such defenses in chicks from three species, Black-legged kittiwake (Rissa tridactyla), Northern fulmar (Fulmarus glacialis), and Herring gull (Larus argentatus), and the relationship with tissue concentrations of essential metals such as selenium and iron and halogenated organic compounds, represented by polychlorinated biphenyl (PCB). The results showed significant species-specific differences in the antioxidant responses which also corresponded with metal and PCB levels in different ways. The capability to neutralize hydroxyl radicals (TOSC-HO•) and the activities of catalase and Se-dependent glutathione peroxidases (GPX) clearly increased in species with the higher levels of metals and PCBs, while the opposite trend was observed for Se-independent GPX, TOSC against peroxyl radicals (ROO•) and peroxynitrite (ONOOH). Less clear relationships were obtained for glutathione levels, GSH/GSSG ratio, glutathione reductase and superoxide dismutase. The results showed differences in antioxidant efficiency between the species, and some of these defenses exhibited dose-response-like relationships with measured levels of selenium, iron and ΣPCBs. PCBs, selenium and iron levels were positively related to the responses of antioxidants with potential to reduce HO•/H₂O₂ (Se-dependent GPX, CAT and TOSC against HO•). However, direct causal relationships between antioxidant responses and contaminant concentrations could not be shown on individual level. Varying levels of metals and contaminants due to different diet and age were probably the main explanations for the species differences in antioxidant defense.
抗氧化防御系统的效率及其与金属和有机污染物体内负荷的关系，以前在北极海鸟中，无论是雏鸟还是成鸟，都没有被研究过。本研究的目的是比较三种鸟类（黑脚三趾鸥、北方巨海燕和银鸥）雏鸟的这些防御机制，并与组织中必需金属（如硒和铁）和卤代有机化合物（以多氯联苯（PCB）表示）的浓度进行比较。结果表明，抗氧化反应存在显著的种间特异性差异，这种差异也以不同的方式与金属和 PCB 水平相关。清除羟自由基（TOSC-HO•）的能力和过氧化氢酶以及硒依赖型谷胱甘肽过氧化物酶（GPX）的活性在金属和 PCB 水平较高的物种中明显增加，而硒非依赖型 GPX、TOSC 清除过氧自由基（ROO•）和过氧亚硝酸盐（ONOOH）的活性则呈现相反的趋势。谷胱甘肽水平、GSH/GSSG 比值、谷胱甘肽还原酶和超氧化物歧化酶的相关性则不太明显。结果表明，不同物种之间的抗氧化效率存在差异，其中一些防御机制与测量的硒、铁和ΣPCBs 水平表现出剂量反应关系。PCBs、硒和铁水平与具有降低 HO•/H₂O₂能力的抗氧化剂的反应呈正相关（硒依赖型 GPX、CAT 和 TOSC 针对 HO•）。然而，不能在个体水平上证明抗氧化反应与污染物浓度之间的直接因果关系。由于不同的饮食和年龄导致的金属和污染物水平的变化，可能是抗氧化防御物种差异的主要解释。
