Department of Biology, Bucknell University, Lewisburg, PA, USA.
Proc Biol Sci. 2012 Apr 7;279(1732):1447-56. doi: 10.1098/rspb.2011.1913. Epub 2011 Nov 9.
Early embryonic exposure to maternal glucocorticoids can broadly impact physiology and behaviour across phylogenetically diverse taxa. The transfer of maternal glucocorticoids to offspring may be an inevitable cost associated with poor environmental conditions, or serve as a maternal effect that alters offspring phenotype in preparation for a stressful environment. Regardless, maternal glucocorticoids are likely to have both costs and benefits that are paid and collected over different developmental time periods. We manipulated yolk corticosterone (cort) in domestic chickens (Gallus domesticus) to examine the potential impacts of embryonic exposure to maternal stress on the juvenile stress response and cellular ageing. Here, we report that juveniles exposed to experimentally increased cort in ovo had a protracted decline in cort during the recovery phase of the stress response. All birds, regardless of treatment group, shifted to oxidative stress during an acute stress response. In addition, embryonic exposure to cort resulted in higher levels of reactive oxygen metabolites and an over-representation of short telomeres compared with the control birds. In many species, individuals with higher levels of oxidative stress and shorter telomeres have the poorest survival prospects. Given this, long-term costs of glucocorticoid-induced phenotypes may include accelerated ageing and increased mortality.
早期胚胎暴露于母体糖皮质激素会广泛影响不同进化谱系的生理和行为。母体糖皮质激素向后代的传递可能是与恶劣环境条件相关的不可避免的代价，或者作为一种母体效应，使后代表型发生变化，为应对压力环境做好准备。无论如何，母体糖皮质激素很可能在不同的发育时间段产生成本和收益。我们操纵了家鸡（Gallus domesticus）的卵黄皮质酮（cort），以研究胚胎暴露于母体应激对幼体应激反应和细胞衰老的潜在影响。在这里，我们报告说，在应激反应的恢复阶段，暴露于卵内实验性增加的 cort 的幼体会出现 cort 持续下降的情况。所有鸟类，无论处理组如何，在急性应激反应中都会转向氧化应激。此外，与对照组相比，cort 的胚胎暴露导致活性氧代谢物水平升高和短端粒过度表达。在许多物种中，氧化应激水平较高和端粒较短的个体的生存前景最差。因此，糖皮质激素诱导表型的长期成本可能包括加速衰老和增加死亡率。
