Fujisawa H, Nishikawa T, Zhu B H, Takeda N, Jujo H, Higuchi K, Hosokawa M
Department of Senescence Biology, Faculty of Medicine, Kyoto University, Japan.
J Gerontol A Biol Sci Med Sci. 1998 Jan;53(1):B11-7. doi: 10.1093/gerona/53a.1.b11.
Accelerated changes in the DNA ploidy associated with in vitro aging were examined in fibroblast-like cells isolated from the dorsal dermis of newborn SAMP11 (accelerated senescence-prone, short-lived) mice, and were compared to changes observed in cell lines from SAMR1 (accelerated senescence-resistant, long-lived) mice. Flow cytometric analysis of the DNA content in confluent cells and chromosome analysis in mitoses revealed that the diploid cells were being replaced with tetraploid cells until a growth crisis; thereafter, hypotetraploid cells became predominant, accompanied by immortalization. The number of mitoses decreased as the crisis ensued, then increased. Although these changes were observed in the cell lines from both strains of mice, the changes occurred more rapidly and at earlier population doublings in the cell lines from the SAMP11 mice. These results suggest that the cell lines from SAMP11 mice might have higher susceptibility to factors that cause polyploidization, including oxidative stress.
在从新生SAMP11（易加速衰老、寿命短）小鼠背部真皮分离出的成纤维细胞样细胞中，研究了与体外衰老相关的DNA倍性加速变化，并与SAMR1（抗加速衰老、寿命长）小鼠细胞系中观察到的变化进行比较。对汇合细胞的DNA含量进行流式细胞术分析以及对有丝分裂中的染色体进行分析表明，二倍体细胞逐渐被四倍体细胞取代，直至生长危机；此后，亚四倍体细胞占主导地位，并伴有永生化。随着危机的出现，有丝分裂次数减少，然后增加。虽然在两种小鼠品系的细胞系中都观察到了这些变化，但在SAMP11小鼠细胞系中，这些变化发生得更快，且在更早的群体倍增时出现。这些结果表明，SAMP11小鼠的细胞系可能对包括氧化应激在内的导致多倍体化的因素更敏感。
