[The long-term limitation of the proliferation of cells in culture does not lead to their proliferative aging].

A hypothesis was tested about a long-term limitation of cell proliferation as the primary cause of their senescence and, consequently, the senescence of the whole organism. Both half-yearly and yearly maintenance of mouse fibroblast-like cells L-929 in a high density permanent culture with low level of mitotic activity (less than 1 mitosis per 10,000 cells) has not revealed any irreversible changes in their proliferative features and has not confirmed the hypothesis under examination.