School of Biological Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia.
Exp Gerontol. 2012 Mar;47(3):211-22. doi: 10.1016/j.exger.2011.11.014. Epub 2012 Jan 2.
The oxidative damage hypothesis of aging posits that the accumulation of oxidative damage is a determinant of an animal species' maximum lifespan potential (MLSP). Recent findings in extremely long-living mammal species such as naked mole-rats challenge this proposition. Among birds, parrots are exceptionally long-living with an average MLSP of 25 years, and with some species living more than 70 years. By contrast, quail are among the shortest living bird species, averaging about 5-fold lower MLSP than parrots. To test if parrots have correspondingly (i) superior antioxidant protection and (ii) lower levels of oxidative damage compared to similar-sized quail, we measured (i) total antioxidant capacity, uric acid and reduced glutathione (GSH) levels, as well as the activities of enzymatic antioxidants (superoxide dismutase, glutathione peroxidase and catalase), and (ii) markers of mitochondrial DNA damage (8-OHdG), protein damage (protein carbonyls) and lipid peroxidation (lipid hydroperoxides and TBARS) in three species of long-living parrots and compared these results to corresponding measures in two species of short-living quails (average MLSP=5.5 years). All birds were fed the same diet to exclude differences in dietary antioxidant levels. Tissue antioxidants and oxidative damage were determined both 'per mg protein' and 'per g tissue'. Only glutathione peroxidase was consistently higher in tissues of the long-living parrots and suggests higher protection against the harmful effects of hydroperoxides, which might be important for parrot longevity. The levels of oxidative damage were mostly statistically indistinguishable between parrots and quails (67%), occasionally higher (25%), but rarely lower (8%) in the parrots. Despite indications of higher protection against some aspects of oxidative stress in the parrots, the pronounced longevity of parrots appears to be independent of their antioxidant mechanisms and their accumulation of oxidative damage.
衰老的氧化损伤假说认为，氧化损伤的积累是决定动物物种最大寿命潜力（MLSP）的一个因素。最近在非常长寿的哺乳动物物种（如裸鼹鼠）中的发现挑战了这一观点。在鸟类中，鹦鹉的平均 MLSP 为 25 年，有些物种的寿命超过 70 年，是特别长寿的物种。相比之下，鹌鹑是寿命最短的鸟类之一，平均 MLSP 比鹦鹉低 5 倍左右。为了测试鹦鹉是否相应地（i）具有更好的抗氧化保护和（ii）比类似大小的鹌鹑氧化损伤水平更低，我们测量了（i）总抗氧化能力、尿酸和还原型谷胱甘肽（GSH）水平，以及酶抗氧化剂（超氧化物歧化酶、谷胱甘肽过氧化物酶和过氧化氢酶）的活性，以及（ii）线粒体 DNA 损伤（8-OHdG）、蛋白质损伤（蛋白质羰基）和脂质过氧化（脂质氢过氧化物和 TBARS）的标志物在三种长寿鹦鹉和两种短寿鹌鹑（平均 MLSP=5.5 年）中，并将这些结果与两种短寿鹌鹑的相应措施进行了比较（平均 MLSP=5.5 年）。所有鸟类都喂食相同的饮食，以排除饮食抗氧化剂水平的差异。组织抗氧化剂和氧化损伤既按“每毫克蛋白质”又按“每克组织”进行测定。只有谷胱甘肽过氧化物酶在长寿鹦鹉的组织中始终较高，表明对氢过氧化物的有害影响有更高的保护作用，这可能对鹦鹉的长寿很重要。在鹦鹉和鹌鹑之间，氧化损伤水平大多在统计学上无显著差异（67%），偶尔更高（25%），但在鹦鹉中很少更低（8%）。尽管鹦鹉在某些方面的氧化应激保护水平较高，但鹦鹉的显著长寿似乎与其抗氧化机制和氧化损伤的积累无关。
