人衰老二倍体成纤维细胞对烷化剂损伤的应答  

Cellular response to DNA damage caused by methyl methanesulfonate (MMS) in human senescent diploid fibroblasts

作　　者：段建明[1] 张宗玉[1] 童坦君[1] 

机构地区：[1]北京大学医学部生物化学与分子生物学系,100083

出　　处：《中华老年医学杂志》2003年第5期288-291,共4页Chinese Journal of Geriatrics

基　　金：国家重点基础研究发展规划资助项目(G2 0 0 0 0 5 70 0 1) ;国家自然科学基金重点资助课题 ( 3 993 0 170 )

摘　　要：目的　观察衰老的人胚肺二倍体成纤维细胞 (2BS)对烷化剂甲磺酸甲酯 (MMS)诱导的DNA损伤的应答。　方法　以体外培养的不同代龄的人胚肺 2BS为对象 ,以MMS诱导DNA损伤 ,以年轻细胞 (<30代 )为对照 ,观察衰老细胞 (>5 5代 )经MMS处理后的细胞形态、增殖特性、细胞周期的改变 ,并分别检测 gadd4 5、p2 1和p5 3等基因转录水平的表达变化 ,同时以非程序性DNA合成(UDS)和单细胞凝胶电泳试验测定DNA修复能力。　结果　经MMS诱导DNA损伤后 ,衰老细胞的细胞形态、生长曲线和细胞周期的变化均不及年轻细胞明显 ;gadd4 5、p2 1和 p5 3等基因的可诱导性表达均低于年轻细胞 ;同时 ,衰老细胞总的及单个细胞的修复能力较年轻细胞明显下降。　结论　衰老 2BS细胞对MMS诱导的DNA损伤后的细胞应答变化能力下降 ,且其修复能力的减退可能与基因的可诱导性表达下降有关。Objective To explore the cellular response of human senescent diploid fibroblasts (2BS) to the DNA damage caused by methyl methanesulfonate (MMS). Methods After MMS treatment, the changes of cell morphology, cell proliferation and all phases in cell cycle of the senescent cells (>55 population doubling, PD) were compared with those of the young cells(<30 PD), and the changes at transcriptional level of gadd45, p21 and p53 genes were also measured at different population doubling(PD) by Northern blot. Meanwhile, the repair competency was examined by the unscheduled DNA synthesis(UDS) and the single cell gel electrophoresis(SCGE). Results After DNA damage induced by MMS, the senescent cells showed less changes in morphology, growth curve and cell cycle than the young cells. The inducible gene expression of gadd45, p21 and p53 in senescent cells declined as compared with that of the young cells. At the same time, the DNA self repair function of senescent 2BS cells significantly declined as compared with that of the young ones ( P <0 01). Conclusions The cellular responsive ability of the senescent 2BS cells to DNA damage caused by MMS declined. The decline of DNA self repair function may also be related to the inducible gene expression by DNA injury.

关 键 词：细胞衰老 DNA损伤 DNA修复 甲磺酸甲酯 

分 类 号：R363[医药卫生—病理学]