Vázquez-Memije Martha E, Cárdenas-Méndez María J, Tolosa Adela, Hafidi Mohammed El
Instituto Mexicano del Seguro Social, Unidad de Investigación Médica en Genética Humana, Centro Médico Nacional Siglo XXI-IMSS. Apdo Postal 73-032, México, DF CP 06725, Mexico.
Exp Gerontol. 2005 Jun;40(6):482-90. doi: 10.1016/j.exger.2005.03.006. Epub 2005 Apr 7.
Throughout the maturation of germ cells, a morphological, biochemical and functional differentiation of mitochondria has been shown to occur. Ageing is known to cause changes involved in energy metabolism. These changes have been related to molecular and functional alterations in the properties of biological membranes. Variations in membrane lipid composition and lipid-protein interactions occur with ageing in several tissues. The present paper describes the relationship between these membrane alterations and the activities of lipid-dependent enzymes of isolated testis mitochondria in rats of from 10 days of age to 24 months. The specific activities of these enzymes are lower in preparations from adult and aged rats as compared to those from young rats. Temperature breaks of Arrhenius plots show age-dependent shifts to higher temperatures for the NADH-dehydrogenase, succinate-dehydrogenase, cytochrome c oxidase, and ATPase in senescent animals. Analysis of the membrane fatty acid composition reveals a distinct age-dependent fall in the content of polyunsaturated fatty acids accompanied by an increase in the proportion of saturated fatty acids and a decrease in polyunsaturated fatty acid percentage. The results suggest that during spermatogenesis and the ageing process some changes in the composition of the fatty acids in the surrounding membrane affect the protein-lipid interactions, producing a decrease in mitochondrial enzyme activities.
在生殖细胞成熟过程中，线粒体已显示出发生形态、生化和功能分化。已知衰老会引起能量代谢相关变化。这些变化与生物膜特性的分子和功能改变有关。在几个组织中，膜脂质组成和脂蛋白相互作用会随衰老而发生变化。本文描述了从10日龄到24月龄大鼠中，这些膜变化与分离的睾丸线粒体脂质依赖性酶活性之间的关系。与幼鼠相比，成年和老年大鼠制剂中这些酶的比活性较低。衰老动物中，阿累尼乌斯曲线的温度转折点显示，NADH脱氢酶、琥珀酸脱氢酶、细胞色素c氧化酶和ATP酶的温度依赖性向更高温度偏移。膜脂肪酸组成分析显示，多不饱和脂肪酸含量明显随年龄下降，同时饱和脂肪酸比例增加，多不饱和脂肪酸百分比降低。结果表明，在精子发生和衰老过程中，周围膜脂肪酸组成的某些变化会影响蛋白质-脂质相互作用，导致线粒体酶活性降低。
