Hayflick L
Mech Ageing Dev. 1979 Mar;9(5-6):393-408. doi: 10.1016/0047-6374(79)90081-2.
The finite in vitro lifetime of cultured normal cells is interpreted to be aging at the cellular level. In addition to the inverse relationship between donor age and population doubling potential (PDP), a number of biochemical and physiological increments and decrements occur prior to the cessation of cell division. The reconstruction of replicating normal human cells from the nuclei of "young" cells and the cytoplasm of "old" cells (and the reverse) suggests that the nucleus governs PDP. Several morphological changes were found to occur in late phase III cells held for up to one year in culture. Autoradiography studies show that (1) a cell population may be composed of several subpopulations, each of which is at a different stage in its life history and (2) lipid synthesis is affected much less as cells age than is DNA, RNA and protein synthesis. Changes occurring in the genetic program of individual cells seem to be the most tenable hypothesis to explain fundamental causes of aging.
培养的正常细胞在体外的有限寿命被解释为细胞水平的衰老。除了供体年龄与群体倍增潜力（PDP）之间的反比关系外，在细胞分裂停止之前还会出现许多生化和生理上的增减变化。用“年轻”细胞的细胞核和“年老”细胞的细胞质（反之亦然）重建复制性正常人类细胞，表明细胞核决定PDP。在培养长达一年的III期晚期细胞中发现了几种形态变化。放射自显影研究表明：（1）一个细胞群体可能由几个亚群组成，每个亚群处于其生命史的不同阶段；（2）随着细胞衰老，脂质合成受影响的程度远小于DNA、RNA和蛋白质合成。单个细胞遗传程序中发生的变化似乎是解释衰老根本原因的最合理假设。
