Pamplona Reinald, Portero-Otín Manuel, Requena Jesus, Gredilla Ricardo, Barja Gustavo
Department of Basic Medical Sciences, Faculty of Medicine, Lleida University, Lleida 25198, Spain.
Mech Ageing Dev. 2002 Sep;123(11):1437-46. doi: 10.1016/s0047-6374(02)00076-3.
In this investigation the effect of 4 months of 40% restriction of calories on defined markers of oxidative, glycoxidative or lipoxidative damage to heart mitochondrial proteins was studied. The protein markers assessed were N(epsilon)-(carboxyethyl)lysine (CEL), N(epsilon)-(carboxymethyl)lysine (CML), N(epsilon)-(malondialdehyde)lysine (MDA-lys), and the recently described (PNAS 98:69-74, 2001) main constituents of protein carbonyls glutamic and aminoadipic semialdehydes. All these markers were measured by gas chromatography/mass spectrometry. The results showed that glutamic semialdehyde was present in rat heart mitochondria at levels 20-fold higher than aminoadipic semialdehyde. After 4 months of caloric restriction, the levels of CEL, CML, MDA-lys and glutamic semialdehyde were significantly lower in the mitochondria from caloric restricted animals than in the controls. These decreases were not due to a lower degree of oxidative attack to mitochondrial proteins, since the rate of mitochondrial oxygen radical generation was not modified by 4 months of caloric restriction. The decreases in MDA-lys and CML were not due either to changes in the sensitivity of mitochondrial lipids to peroxidation since measurements of the fatty acid composition showed that the total number of fatty acid double bonds and the peroxidizability index were not changed by caloric restriction. The results globally indicate that caloric restriction during 4 months decreases oxidative stress-derived damage to heart mitochondrial proteins. They also suggest that these decreases are due to an increase in the capacity of the restricted mitochondria to decompose oxidatively modified proteins.
在本研究中，我们探究了4个月40%热量限制对心脏线粒体蛋白质氧化、糖氧化或脂氧化损伤特定标志物的影响。所评估的蛋白质标志物包括N（ε）-（羧乙基）赖氨酸（CEL）、N（ε）-（羧甲基）赖氨酸（CML）、N（ε）-（丙二醛）赖氨酸（MDA-lys），以及最近报道的（《美国国家科学院院刊》98:69 - 74，2001）蛋白质羰基的主要成分谷氨酸半醛和氨基己二酸半醛。所有这些标志物均通过气相色谱/质谱法进行测定。结果显示，谷氨酸半醛在大鼠心脏线粒体中的含量比氨基己二酸半醛高20倍。经过4个月的热量限制后，热量限制组动物线粒体中CEL、CML、MDA-lys和谷氨酸半醛的水平显著低于对照组。这些降低并非由于线粒体蛋白质氧化攻击程度降低，因为热量限制4个月并未改变线粒体氧自由基的生成速率。MDA-lys和CML的降低也不是由于线粒体脂质对过氧化敏感性的改变，因为脂肪酸组成测量表明，脂肪酸双键总数和过氧化指数并未因热量限制而改变。总体结果表明，4个月的热量限制可减少氧化应激对心脏线粒体蛋白质的损伤。研究结果还表明，这些降低是由于受限线粒体分解氧化修饰蛋白质的能力增强所致。
