Gao J J, Lai C Y, Zhang W J, Yang X F
Department of Public Health and Preventive Medicine, School of Medicine, Jinan University, Guangzhou 510632, China.
Food Safety and Health Research Center/School of Public Health, Southern Medical University, Guangzhou 510515, China.
Zhonghua Yu Fang Yi Xue Za Zhi. 2019 Mar 6;53(3):309-315. doi: 10.3760/cma.j.issn.0253-9624.2019.03.014.
To study the alterations of mitochondrial biological characteristics during both cellular replicative and premature senescence induced by hydrogen peroxide in human embryonic lung fibroblasts (HEFs). The premature senescence was induced by 400 μmol/L H(2)O(2) once a day at the same time and with 2 hours each time, after four consecutive days the premature senescence models were classified into premature senescence initiation group (PSi) and premature senescence persistence group (PSp). Based on the life span of HEFs, the cell replicative senescence was divided into five groups included young-age (22 PDL), middle-age (35 PDL), replicative senescence (49 PDL), PSi and PSp. The mitochondrial distribution, relative content, adenosine triphosphate (ATP) contents, 8-hydroxydeoxyguanosine (8-OHdG) levels, the relative mitochondrial transcription factor A (TFAM) as well as mitochondrial DNA methyltransferase 1 (mtDNMT1) mRNA levels, mtDNA copy number, the relative TFAM protein level and the total enzyme activity of mitochondrial DNA methyltransferases (mtDNMTs) were detected in five senescence groups. The mtDNA copy number, 8-OHdG contents, level of mtDNMT1 mRNA and mtDNMTs activity in 49 PDL group were higher than those in 22 PDL group (all values <0.05); The level of 8-OHdG in PSi was higher than that in 22 PDL group (0.05); The ATP contents, mtDNA copy number, the mRNA and protein expression levels of TFAM and mtDNMTs activity of PSp were higher than those in 22 PDL group (all values<0.05). During the cellular senescence of HEFs, the higher mtDNA copy number and mtDNMTs activity were common features regardless of replicative or premature senescence, with possibility that oxidative stress was involved in modifying the occurrence of premature senescence.
研究过氧化氢诱导人胚肺成纤维细胞（HEFs）细胞复制性衰老和早衰过程中线粒体生物学特性的变化。每天一次用400μmol/L H₂O₂诱导早衰，每次处理2小时，连续处理四天后，将早衰模型分为早衰起始组（PSi）和早衰持续组（PSp）。根据HEFs的寿命，将细胞复制性衰老分为五组，包括年轻组（22代群体倍增水平，PDL）、中年组（35 PDL）、复制性衰老组（49 PDL）、PSi组和PSp组。检测五组衰老细胞的线粒体分布、相对含量、三磷酸腺苷（ATP）含量、8-羟基脱氧鸟苷（8-OHdG）水平、相对线粒体转录因子A（TFAM）以及线粒体DNA甲基转移酶1（mtDNMT1）mRNA水平、mtDNA拷贝数、相对TFAM蛋白水平和线粒体DNA甲基转移酶（mtDNMTs）的总酶活性。49 PDL组的mtDNA拷贝数、8-OHdG含量、mtDNMT1 mRNA水平和mtDNMTs活性高于22 PDL组（所有值<0.05）；PSi组的8-OHdG水平高于22 PDL组（P<0.05）；PSp组的ATP含量、mtDNA拷贝数、TFAM的mRNA和蛋白表达水平以及mtDNMTs活性高于22 PDL组（所有值<0.05）。在HEFs细胞衰老过程中，无论复制性衰老还是早衰，较高的mtDNA拷贝数和mtDNMTs活性都是共同特征，氧化应激可能参与了早衰的发生。
