Time-lapse cinemicrophotographic studies of cell division patterns of human diploid fibroblasts (WI-38) during their in vitro lifespan.

Genealogies of human diploid embryonic lung fibroblasts, WI-38 were prepare from analysis of filmed sequences of clones at passages 20, 28 and 53. The results indicate heterogeneity in cell division patterns, interdivision time and migration activity. The relationship of the cell division patterns to age of culture is difficult to assess at this time because of the heterogeneity of the clones, however, the late passage culture appeared to be more variable in terms of sister-sister, and mother-daughter relationships. The passage 28 culture was representative of a highly proliferating clone, exhibiting short interdivision times and a synchronous division pattern. The passage 20 and 53 clones exhibited longer interdivision times and less synchronous division pattern than the passage 28 clone. A gradual lengthening of average interdivision time with successive generations has been observed in all genealogies regardless of passage level of the donor culture. A portion of daughter cells in the fifth and sixth generation exhibited lower interdivision time than the mother cell. The effects of nutrients, space, and mitotic inhibitors or stimulators on interdivision time of the cells within the clones is discussed.