Mitochondrial DNA mutations and associated defects in cytochrome c oxidase (COX) are proposed to play an important role in human ageing; however there have been limited studies on the frequency of these defects in normal mouse ageing. Here we compare COX-deficiency in two epithelial tissues; the colon and the ciliary epithelium, from human and mouse. The pattern of accumulation of COX-deficiency is similar in both tissues in the two species; however the frequency of colonic crypts with COX-deficiency in aged humans is significantly higher than in aged mice, whereas the levels of COX-deficiency in the ciliary epithelium are higher in the mouse than in humans. This suggests the impact of mitochondrial defects on normal ageing may differ significantly between species.

中文翻译：

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小鼠和人类线粒体缺陷随年龄增长的差异。

线粒体 DNA 突变和细胞色素 c 氧化酶 (COX) 的相关缺陷被认为在人类衰老中起重要作用；然而，关于这些缺陷在正常小鼠衰老中出现的频率的研究有限。在这里，我们比较了两种上皮组织中的 COX 缺陷；结肠和睫状上皮，来自人和小鼠。两个物种的两种组织中 COX 缺乏的积累模式相似；然而，老年人类结肠隐窝中 COX 缺乏的频率明显高于老年小鼠，而小鼠睫状上皮中 COX 缺乏的水平高于人类。这表明线粒体缺陷对正常衰老的影响可能因物种而异。