Plasma markers of oxidative stress are uncorrelated in a wild mammal.
Plasma markers of oxidative stress are uncorrelated in a wild mammal.
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DOI：
10.1002/ece3.1771
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发表时间：
2015-11
影响因子：
2.6
通讯作者：
Nussey DH
中科院分区：
文献类型：
--
作者：
Christensen LL;Selman C;Blount JD;Pilkington JG;Watt KA;Pemberton JM;Reid JM;Nussey DH
氧化应激是由潜在破坏性的活性氧物种的产生与抗氧化剂防御和修复机制之间的失衡造成的，已被认为是生活史权衡的重要中介。存在大量与氧化应激相关的生物标记物，但很少有生态学研究检查经历自然条件的生物体中不同标记物之间的关系，或测试这些关系在不同环境和人口群体中是否稳定。因此，目前还不清楚不同标记物的研究可以在多大程度上进行比较，也不清楚专注于单一标记物的研究是否可以得出关于氧化应激的一般性结论。我们在圣基尔达的一个野生索伊绵羊种群中，测量了在4年时间里收集的706个血浆样本中广泛使用的氧化损伤标记物(蛋白质羰基和丙二醛)和抗氧化防御(超氧化物歧化酶和总抗氧化能力)。我们量化了这四个标记在整个样本组以及不同年份、年龄组(羔羊和成年羊)和性别之间的相关性结构。当将所有4年的数据汇集在一起时，我们发现一些标记对之间有一些中等强的相关性。然而，这些相关性是由平均标记值的相当大的年间变化引起的；相关系数很小，在考虑年间变化后与零没有显著差异。此外，在每个年份、年龄和性别亚组内，四个标记之间的成对相关系数很弱，不显著，且分布在零附近。此外，主成分分析证实这四个标记代表四个独立的变异轴。我们的结果表明，氧化应激的血浆标志物可能会因环境条件的不同而在不同年份之间发生巨大变化，即使在同一亚组内没有任何相关性的情况下，这种变化也可以在群体水平上诱导标志物之间的相关性。在年内或人口亚组内没有任何一致的相关性意味着，在根据观察到的与氧化应激标志物的关系进行概括时必须谨慎，因为每个标志物可能反映不同的和潜在的不耦合的生化过程。
Oxidative stress, which results from an imbalance between the production of potentially damaging reactive oxygen species versus antioxidant defenses and repair mechanisms, has been proposed as an important mediator of life‐history trade‐offs. A plethora of biomarkers associated with oxidative stress exist, but few ecological studies have examined the relationships among different markers in organisms experiencing natural conditions or tested whether those relationships are stable across different environments and demographic groups. It is therefore not clear to what extent studies of different markers can be compared, or whether studies that focus on a single marker can draw general conclusions regarding oxidative stress. We measured widely used markers of oxidative damage (protein carbonyls and malondialdehyde) and antioxidant defense (superoxide dismutase and total antioxidant capacity) from 706 plasma samples collected over a 4‐year period in a wild population of Soay sheep on St Kilda. We quantified the correlation structure among these four markers across the entire sample set and also within separate years, age groups (lambs and adults), and sexes. We found some moderately strong correlations between some pairs of markers when data from all 4 years were pooled. However, these correlations were caused by considerable among‐year variation in mean marker values; correlation coefficients were small and not significantly different from zero after accounting for among‐year variation. Furthermore, within each year, age, and sex subgroup, the pairwise correlation coefficients among the four markers were weak, nonsignificant, and distributed around zero. In addition, principal component analysis confirmed that the four markers represented four independent axes of variation. Our results suggest that plasma markers of oxidative stress may vary dramatically among years, presumably due to environmental conditions, and that this variation can induce population‐level correlations among markers even in the absence of any correlations within contemporaneous subgroups. The absence of any consistent correlations within years or demographic subgroups implies that care must be taken when generalizing from observed relationships with oxidative stress markers, as each marker may reflect different and potentially uncoupled biochemical processes.