Figure 2. Growth curves of primary rodent fibroblasts.
Cells were isolated from skin and lung tissue and grown at 3% oxygen. The number of donors for each species is shown in Figure 1. (A) Species that use replicative senescence. Each curve is an average of at least 5 independent cultures, and error bars show s.d. Beaver cultures entered senescence at PD39±10; porcupine and paca cultures entered senescence at PD22±3; and capybara cultures senesced at PD25±8. Human primary fibroblasts culture HCA2 is shown as a reference. (B) Rodents that do not use replicative senescence fall into two groups: fast growing and slow growing. Each curve is an average of at least 5 independent cultures, and error bars show s.d. (C) Growth of grey squirrel embryonic fibroblasts (SEFs). Cells grow rapidly for the first 30 PDs, and then slow down and attain the growth rate of adult cells. SEFs were isolated from 4 embryos derived from 2 pregnant females.