Effects of the number of cell divisions and of added isologous nucleic acids on ageing of normal human fibroblasts in vitro
Mellgren, J.
Pathologia Europaea 10(3): 215-219
1975
ISSN/ISBN: 0031-2967 PMID: 1187198 Document Number: 95136
Whether the life span of a normal cell strain in vitro depends on the number of cell divisions passed or simply on metabolic time in culture is a matter of debate. Sub-strains of the same normal human fetal fibroblast strain were cultured, separated in a common dish with a common medium. One sub-strain was forced by infrequent transfers to grow slowly, the other was transferred frequently and grew freely. At intervals, cell kinetics of the strains was registered by time-lapse photography. Aging in vitro, manifested by changes of cell kinetics, and the total life span in vitro for normal human fibroblasts were dependent on the number of cell divisions passed, supporting the idea of a progressive decay of the transcription mechanism. A trial to postpone aging of normal human fetal fibroblasts in vitro was made by adding nucleic acids, extracted from other organs of the same ovum, to the medium for 7-14 transfers. Four to 18 transfers after the end of the treatment, the cells still revealed a kinetic pattern typical of much younger normal strains, pointing to an influence on the genes. The effect is probably due to the DNA of the nucleic acid extract.