Colgate University, Department of Biology, Hamilton, New York.
State University of New York College of Environmental Science and Forestry, Department of Environmental Science and Forestry, Syracuse, New York.
Am J Physiol Regul Integr Comp Physiol. 2020 Aug 1;319(2):R203-R210. doi: 10.1152/ajpregu.00067.2020. Epub 2020 Jul 1.
Canids are a morphological and physiological diverse group of animals, with the most diversity found within one species, the domestic dog. Underlying observed morphological differences, there must also be differences at other levels of organization that could lead to elucidating aging rates and life span disparities between wild and domestic canids. Furthermore, small-breed dogs live significantly longer lives than large-breed dogs, while having higher mass-specific metabolic rates and faster growth rates. At the cellular level, a clear mechanism underlying whole animal traits has not been fully elucidated, although oxidative stress has been implicated as a potential culprit of the disparate life spans of domestic dogs. We used plasma and red blood cells from known aged domestic dogs and wild canids, and measured several oxidative stress variables: total antioxidant capacity (TAC), lipid damage, and enzymatic activities of catalase, superoxide dismutase, and glutathione peroxidase (GPx). We used phylogenetically informed general linear mixed models and nonphylogenetically corrected linear regression analysis. We found that lipid damage increases with age in domestic dogs, whereas TAC increases with age and TAC and GPx activity increases as a function of age/maximum life span in wild canids, which may partly explain longer potential life spans in wolves. As body mass increases, TAC and GPx activity increase in wild canids, but not domestic dogs, highlighting that artificial selection may have decreased antioxidant capacity in domestic dogs. We found that small-breed dogs have significantly higher circulating lipid damage compared with large-breed dogs, concomitant to their high mass-specific metabolism and higher growth rates, but in opposition to their long life spans.
犬科动物是形态和生理多样性的动物群体，其中最具多样性的是一种物种，即家犬。在观察到的形态差异背后，其他组织层面也必然存在差异，这些差异可能会揭示野生动物和家养犬之间衰老速度和寿命差异的原因。此外，小型犬的寿命明显长于大型犬，而其比代谢率更高，生长速度更快。在细胞水平上，尚未完全阐明导致整体动物特征的明确机制，尽管氧化应激已被认为是导致家养犬寿命差异的潜在罪魁祸首之一。我们使用了来自已知年龄的家养犬和野生犬科动物的血浆和红细胞，并测量了几种氧化应激变量：总抗氧化能力（TAC）、脂质损伤以及过氧化氢酶、超氧化物歧化酶和谷胱甘肽过氧化物酶（GPx）的酶活性。我们使用了基于系统发育的广义线性混合模型和非基于系统发育的线性回归分析。我们发现，脂质损伤随家养犬年龄的增长而增加，而 TAC 随年龄的增长而增加，TAC 和 GPx 活性随野生犬科动物的年龄/最大寿命的增加而增加，这可能部分解释了狼的潜在寿命更长。随着体重的增加，野生犬科动物的 TAC 和 GPx 活性增加，但家养犬没有，这突出表明人工选择可能降低了家养犬的抗氧化能力。我们发现，与大型犬相比，小型犬的循环脂质损伤明显更高，这与其高比代谢率和更高的生长速度有关，但与它们的长寿命相反。
