Fig. 3.
Effect of estrogen on cellular senescence. (a) The relative levels of SA-β-gal-positive staining cells in different PDL when HUVECs were untreated and treated with 10−8 M E2 for 24 h. Positive staining cells were evaluated by FACscan. (b) Representative photographs of SA-β-gal staining in control, 10−8 M E2-treated, and 10−8 M E2- and 10−4 M l-NAME-treated cells. Note that treatment with E2 decreased the number of SA-β-gal-positive cells, which was prevented by further treatment with l-NAME. Cells were used in PDL 22 at passage 7. (c) The effects of E2 (E, 10−8 M), ICI 182780 (I, 1 μM), and l-NAME (N, 1 mM) on telomerase activity in HUVECs. UD, undetectable. ∗∗, P < 0.01 vs. control.