Weindruch R H, Cheung M K, Verity M A, Walford R L
Mech Ageing Dev. 1980 Apr;12(4):375-92. doi: 10.1016/0047-6374(80)90070-6.
Effects of aging and of dietary restriction on mitochondrial recovery and respiratory capacities have been assessed in mice. Old mice (23-26 months) did not differ from adult mice (9-12 months) in amounts of protein recovered in mitochondrial fractions of liver, brain and spleen, but did show a decline in specific activity of cytochrome c oxidase (cyt. c ox.) in liver and spleen. Age effects on in vitro respiration by mitochondria occurred in liver and spleen. In liver, only one substrate (beta-hydroxybutyrate) of four tested was respired at a different rate by old than by young mitochondria. Depression of state 3 respiration and 2,4-dinitrophenol (DNP)-uncoupled rates was observed for this substrate; however, this effect depended on expressing respiration on the basis of mitochondrial protein and was less overt if data were expressed per unit of cyt. c ox. activity. Old spleen mitochondria exhibited a grosser defect, showing a 40% decrease in the respiratory control index (RCI) for (succinate + rotenone)- supported respiration (the only substrate tested) due to a possible increase in state 4 rates. Effects of dietary restriction were assessed in liver and brain of 3-7-month-old mice underfed since weaning. Dietary restriction reduced recovery of total liver mitochondrial protein and liver cyt. c ox. specific activity. Liver mitochondria from restricted mice generally showed increased state 3 rates with no differences from controls in state 4 rates for respiration supported by glutamate or pyruvate + malate, resulting in an increased RCI for these substrates. DNP-uncoupled rates were also raised by dietary restriction. Unlike effects observed in old versus young mice, these differences obtained whether the data were expressed on the basis of mitochondrial protein or on cyt. c ox. activity. Electron microscopy of liver mitochondrial preparations revealed more non-mitochondrial contaminants in old mice and larger mitochondria in dietarily restricted mice. These findings are compatible with reports of age-dependent losses of liver mitochondria and suggest that dietary restriction may retard this loss.
衰老和饮食限制对小鼠线粒体恢复及呼吸能力的影响已得到评估。老年小鼠（23 - 26个月）肝脏、大脑和脾脏线粒体部分回收的蛋白量与成年小鼠（9 - 12个月）并无差异，但肝脏和脾脏中细胞色素c氧化酶（cyt. c ox.）的比活性确实出现了下降。衰老对肝脏和脾脏中线粒体的体外呼吸有影响。在肝脏中，所测试的四种底物中只有一种（β-羟基丁酸），老年线粒体与年轻线粒体的呼吸速率不同。观察到该底物的状态3呼吸和2,4-二硝基苯酚（DNP）解偶联速率受到抑制；然而，这种影响取决于以线粒体蛋白为基础来表示呼吸作用，如果数据以每单位cyt. c ox.活性来表示，则不太明显。老年脾脏线粒体表现出更严重的缺陷，对于（琥珀酸 + 鱼藤酮）支持的呼吸作用（唯一测试的底物），呼吸控制指数（RCI）下降了40%，这可能是由于状态4速率可能增加所致。对自断奶起就进食不足的3 - 7个月大的小鼠的肝脏和大脑进行了饮食限制的影响评估。饮食限制降低了肝脏线粒体总蛋白的回收率以及肝脏cyt. c ox.的比活性。来自饮食受限小鼠的肝脏线粒体通常显示状态3速率增加，对于由谷氨酸或丙酮酸 + 苹果酸支持的呼吸作用，其状态4速率与对照组无差异，导致这些底物的RCI增加。饮食限制也提高了DNP解偶联速率。与老年小鼠和年轻小鼠之间观察到的影响不同，无论数据是以线粒体蛋白还是以cyt. c ox.活性为基础来表示，这些差异都存在。肝脏线粒体制剂的电子显微镜检查显示，老年小鼠中有更多非线粒体污染物，而饮食受限小鼠中的线粒体更大。这些发现与关于肝脏线粒体随年龄增长而损失的报道一致，并表明饮食限制可能会减缓这种损失。
