Figure 2. TGF-β1 induces cellular senescence in B4G12 cells. (A-B) The G1 phase arrest was induced by TGF-β1 treatment. Control and TGF-β1–treated B4G12 cells were subjected to cell cycle analysis after 48h-treatment. A representative ﬂow cytometric analysis of the DNA content was shown in (A) and the values are mean±SD in (B). (C-D) SA-β-Gal activity was measured in B4G12 cells treated with 10 ng/ml TGF-β1 alone, or in combination with NAC (10mM) for 72h. NAC treatment alone (10mM) did not affect the cell cycle status and SA-β-Gal activity. Bar graphs represent mean±SD. *P<0.05, **P<0.01. All the experiments were independently repeated at least three times.