不同年龄人群肌肉组织中7种线粒体酶的表达差异

Differential expression of seven mitochondrial enzymes in young and old skeletal muscles

目的:探讨年轻人与中老年人肌肉中线粒体电子传递链和胞质中一些关键酶的表达差异。方法:收集7例年轻人及33例中老年人颈部肌肉标本,透射电镜观察两组肌肉中线粒体形态学变化,免疫组织化学染色和蛋白质印迹检测NADH氧化还原酶辅酶1[NADH dehydrogenase(ubiquinone)1 alpha subcomplex 1,NDUFA1],琥珀酸脱氢酶复合体铁硫亚基(succinate dehydrogenase complex,subunit B,SDHB),细胞色素b(cytochrome b,Cytb),细胞色素C氧化酶(cytochrome C oxidase,COX),V型H+ATP酶(vacuolar-type H+-ATPase,V-ATPase H),苹果酸脱氢酶(cytosolic malate dehydrogenase,MDH)、短链羟烷基-辅酶A脱氢酶(hydroxyacyl-coenzyme A dehydrogenase,HADHSC)的表达情况。结果:与年轻人相比,中老年人肌肉中线粒体体积增大,空泡增多,嵴排列紊乱,出现类结晶状包涵体;NDUFA1、SDHB、Cytb、COX、V-ATPase H表达量明显降低(P均<0.05),但MDH及HADHSC的表达差异无统计学意义;蛋白质印迹结果与免疫组织化学结果相一致。结论:肌肉组织中线粒体的形态和关键酶的表达随年龄的增加出现明显改变,可能在衰老过程中起到重要作用。

Objective： To study the relationship between muscular function and ageing by comparing the morphologic and enzymatic expressions of muscular mitochondrion in different age groups. Methods ： Speci- mens of neck muscles were collected from 7 young patients and 33 old patients who underwent neck surgery. The morphological changes of mitochondrial were demonstrated by electronic microscope, whereas the expressions of NADH dehydrogenase （ubiquinone） 1 alpha subcomplex 1 （NDUFA1）, succinate dehydrogenase complex（SDHB）, cytochrome b （Cytb）, cytochrome c oxidase （COX）, vacuolar-type H＋ ATPase （V-ATPase H）, cytosolic malate dehydrogenase （MDH） and hydroxyacyl-coenzyme A dehydrogenase （HADHSC） were detected by immunohistochemical staining and western blotting. Results： Compared with the young patients, the mitochondria in elder patients became larger, and had more accumulating vacuoles, cristae abnormalities and intra-mitochondrial paracrystalline inclusions; meanwhile, the expressions of NDUFAI, SDHB, Cytb, COX, V-ATPase H decreased significantly in elder patients than young patients （both P 〈0.05）. However, there was no difference in expression of MDH and HADHSC between young patients and old patients. These results were consistent with western blotting. Conclusion ： The morphologic and enzymatic function of muscular mitochondria degenerated along with ageing, which might play an important role in ageing.