Aging of chick embryo fibroblasts in vitro—I. Saturation density and population doubling rate

Abstract

The saturation density and population doubling rate of chick embryonic fibroblasts were precisely determined. In conflict with previous observations, their saturation density continued to decrease exponentially without any plateau through the lifespan. In some cell lines, population doubling rate remained constant over the first half of lifespan. On the other hand, the rate of the others declined from the beginning of culture. In the latter case, the cell lines may be somewhat injured. As relative to the cell lines obtained from chick trunks, the lines from the skin and muscle of chick legs showed an analogous aging pattern with each other. This suggests that the heterogeneity of original cells in starter cultures is responsible for the rather large variations of aging pattern between different chick cell lines.