Figure 2. Flow cytometric analysis of cell cycle distribution of senescent REFs (passages 1 and 9 and REF cells treated by rapamycin (passage 19). Cells at different passages of culturing were prepared as described in the section “Flow cytometry” and analyzed for G₁, S, and G₂ phase ratio. (A) REF, passage 1 without rapamycin; (B) REF, passage 9 without rapamycin; (C) Rapamycin-derived cells, passage 19 (rapamycin treatment of REFs during passages from 7–10).