Department of Biology, University of Turku, Turku, Finland.
Department of Biology, University of Turku, Turku, Finland.
Sci Total Environ. 2017 Jan 1;575:841-848. doi: 10.1016/j.scitotenv.2016.09.131. Epub 2016 Sep 30.
Telomere length may reflect the expected life span and possibly individual quality. Environmental stressors are known to increase oxidative stress and accelerate telomere attrition: however the interactions between redox status and telomere dynamics are not fully understood. We investigated whether exposure to heavy metal pollution is associated with oxidative stress and telomere damage in two insectivorous passerines, the Great tit (Parus major) and the Pied flycatcher (Ficedula hypoleuca). We were also interested to know whether within-brood competition could influence the nestling redox status or telomere length. Breeding females and nestlings were sampled near the point pollution source and compared to birds in non-polluted control zone. We measured heavy metal concentrations, calcium, metallothioneins, telomere lengths and redox status (oxidative damage, and enzymatic and non-enzymatic antioxidants) in liver samples. Great tit nestlings in the polluted zone had significantly shorter telomeres compared to those in the unpolluted control zone. In addition, those great tit nestlings that were lighter than their average siblings, had shorter telomeres compared to the heavier ones. In pied flycatchers neither pollution nor growth stress were associated with telomere length, but adult females had significantly shorter telomeres compared to the nestlings. All the results related to redox status varied remarkably among the species and the age groups. In both species antioxidants were related to pollution. There were no significant associations between redox status and telomere length. Our results suggest that wild birds at a young age are vulnerable to pollution and growth stress induced telomere damage. Redox status seems to interact with pollution and growth, but more studies are needed to clarify the underlying physiological mechanisms of telomere attrition. Our study highlights that all the observed associations and differences between the sampling zones varied depending on the species, age, and degree of exposure to pollution.
端粒长度可能反映预期寿命和个体质量。已知环境应激原会增加氧化应激并加速端粒磨损：然而，氧化还原状态和端粒动力学之间的相互作用尚未完全理解。我们研究了重金属污染暴露是否与两种食虫雀形目鸟类——大山雀（Parus major）和白腰文鸟（Ficedula hypoleuca）中的氧化应激和端粒损伤有关。我们还想知道巢内竞争是否会影响雏鸟的氧化还原状态或端粒长度。繁殖雌鸟和雏鸟在污染源附近采样，并与未受污染的对照区的鸟类进行比较。我们测量了肝脏样本中的重金属浓度、钙、金属硫蛋白、端粒长度和氧化还原状态（氧化损伤以及酶和非酶抗氧化剂）。受污染区的大山雀雏鸟的端粒明显短于未受污染的对照区。此外，与较重的雏鸟相比，那些比平均兄弟姐妹轻的大山雀雏鸟的端粒更短。在白腰文鸟中，污染和生长压力都与端粒长度无关，但成年雌鸟的端粒明显短于雏鸟。所有与氧化还原状态相关的结果在物种和年龄组之间差异显著。在这两个物种中，抗氧化剂与污染有关。氧化还原状态与端粒长度之间没有显著关联。我们的研究结果表明，处于幼年期的野生鸟类容易受到污染和生长压力引起的端粒损伤。氧化还原状态似乎与污染和生长相互作用，但需要更多的研究来阐明端粒磨损的潜在生理机制。我们的研究强调，观察到的所有关联和采样区之间的差异取决于物种、年龄和暴露于污染的程度。
