Animal response to stressors such as harsh environmental conditions and demanding biological processes requires energy generated through increased mitochondrial activity. This results in the production of reactive oxygen species (ROS). In vitro and some in vivo studies suggest that oxidative damage of DNA caused by ROS is responsible for telomere shortening. Since telomere length is correlated with survival in many vertebrates, telomere loss is hypothesised to trigger cellular ageing and/ or to reflect the harshness of the environment an individual has experienced. To improve our understanding of stress-induced telomere dynamics in non-human vertebrates, we analysed 109 relevant studies in a meta-analytical framework. Overall, the exposure to possible stressors was associated with shorter telomeres or higher telomere shortening rate (average effect size = -0.16 ± 0.03). This relationship was consistent for all phylogenetic classes and for all a priori-selected stressor categories. It was stronger in the case of pathogen infection, competition, reproductive effort and high activity level, which emphasises their importance in explaining intraspecific telomere length variability and, potentially, lifespan variability. Interestingly, the association between stressor exposure and telomeres in one hand, and oxidative stress in the other hand, covaried, suggesting the implication of oxidative stress in telomere dynamics.

中文翻译：

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非人类脊椎动物压力源和端粒之间的关联：荟萃分析。

动物对恶劣环境条件和苛刻的生物过程等压力源的反应需要通过增加线粒体活动产生的能量。这导致产生活性氧（ROS）。体外和一些体内研究表明，由 ROS 引起的 DNA 氧化损伤是端粒缩短的原因。由于端粒长度与许多脊椎动物的生存相关，因此假设端粒损失会引发细胞老化和/或反映个体所经历的环境的严酷程度。为了提高我们对非人类脊椎动物应激诱导的端粒动力学的理解，我们在元分析框架中分析了 109 项相关研究。全面的，暴露于可能的压力源与较短的端粒或较高的端粒缩短率相关（平均效应大小 = -0.16 ± 0.03）。这种关系对于所有系统发育类别和所有先验选择的压力源类别都是一致的。在病原体感染、竞争、繁殖努力和高活动水平的情况下，它更强，这强调了它们在解释种内端粒长度变异性以及潜在的寿命变异性方面的重要性。有趣的是，一方面压力源暴露与端粒之间的关联，另一方面与氧化应激之间的关联是协变的，这表明氧化应激在端粒动力学中的意义。在病原体感染、竞争、繁殖努力和高活动水平的情况下，它更强，这强调了它们在解释种内端粒长度变异性以及潜在的寿命变异性方面的重要性。有趣的是，一方面压力源暴露与端粒之间的关联，另一方面与氧化应激之间的关联是协变的，这表明氧化应激在端粒动力学中的意义。在病原体感染、竞争、繁殖努力和高活动水平的情况下，它更强，这强调了它们在解释种内端粒长度变异性以及潜在的寿命变异性方面的重要性。有趣的是，一方面压力源暴露与端粒之间的关联，另一方面与氧化应激之间的关联是协变的，这表明氧化应激在端粒动力学中的意义。