Experimental design, growth curves and transition into senescence.

<p>(A) Experimental plan of culturing fibroblast cell strains derived from a single vial and maintained in culture as triplicates from an early PD until senescence at late PDs. (B) Growth curve of five different fibroblast cell strains (MRC-5, BJ, WI-38, IMR-90, HFF) derived from a single vial and maintained in culture as triplicates from an early PD until senescence at late PDs. Data points of all measurements are displayed (not the mean). (C) Percentage of SA-β Gal positive cells at different time points of their growth in culture in the five fibroblast strains derived from a single vial. Each curve is measured in triplicate, the mean value is displayed with error bar (± S.E).