Li J, Zhang Z, Tong T
Department of Biochemistry and Molecular Biology, Beijing Medical University, China.
Mech Ageing Dev. 1995 Apr 21;80(1):25-34. doi: 10.1016/0047-6374(94)01557-3.
The limited replicative lifespan of diploid human cells in vitro (cellular senescence) serves as a cellular model of aging. We examined the proliferative response of 2BS cells of different population doubling levels to fibroblast growth factor (FGF). DNA synthesis was measured by thymidine incorporation. As the cells aged, there was a significant decrease in the stimulation of DNA synthesis by FGF addition (P < 0.01). The effective concentration of FGF and the latent period prior to DNA synthesis did not change. Expression of Rb and p53 mRNA after growth factor stimulation was also examined. Young and old cells had similar Rb mRNA levels, whereas the p53 mRNA level was significantly reduced in old cells. After both cells were treated by FGF or epidermal growth factor (EGF), Rb expression increased 210-275% in young cells and 50-60% in old ones. However, no significant change was found in p53 gene transcriptions after FGF addition. The results further suggest that cell aging is associated with a progressive loss of the ability of cells to respond to growth factors.
二倍体人类细胞在体外的有限复制寿命（细胞衰老）是衰老的一种细胞模型。我们检测了不同群体倍增水平的2BS细胞对成纤维细胞生长因子（FGF）的增殖反应。通过胸腺嘧啶核苷掺入法测定DNA合成。随着细胞衰老，添加FGF对DNA合成的刺激显著降低（P<0.01）。FGF的有效浓度和DNA合成前的潜伏期没有变化。还检测了生长因子刺激后Rb和p53 mRNA的表达。年轻细胞和衰老细胞的Rb mRNA水平相似，而衰老细胞中的p53 mRNA水平显著降低。在用FGF或表皮生长因子（EGF）处理这两种细胞后，年轻细胞中Rb表达增加210 - 275%，衰老细胞中增加50 - 60%。然而，添加FGF后p53基因转录未发现显著变化。结果进一步表明细胞衰老与细胞对生长因子反应能力的逐渐丧失有关。
