Figure 2. NORAD-knockdown is results in the cell cycle arrest in G0/G1 phase and aggravates ox-LDL-induced senescence of HUVECs. HUVECs were transfected with siNORAD or scrambled siCTRL. After transfection for 24 h, the cells were treated with 60 μg/mL ox-LDL for 24 h. (A) HUVECs were stained to determine SA-β-gal. NORAD-knockdown increased the number of positive-stained cells after they were treated with ox-LDL. Results were representative of three separate experiments. (B) mRNA expression of p53 in ox-LDL-treated HUVECs through RT-qPCR (n = 3, *P < 0.05 vs. siCTRL, #P < 0.05 vs. siCTRL+ox-LDL). (C) mRNA expression of p21 in ox-LDL-treated HUVECs through RT-qPCR (n = 3, *P < 0.05 vs. siCTRL, ##P < 0.01 vs. siCTRL+ox-LDL). (D) mRNA expression of p53 in young and senile HUVECs through RT-qPCR (n = 3, *P < 0.05 vs. Youth). (E) mRNA expression of p21 in young and senile HUVECs through RT-qPCR (n = 3, ##P < 0.05 vs. Youth). (F) NORAD levels in young and senile HUVECs through qRT-PCR (n = 3, *P < 0.05 vs. Youth). (G) NORAD silencing induced ox-LDL-treated cell cycle arrest at G0/G1 phase. Flow cytometry was used to detect the cell cycle distribution of ox-LDL-treated HUVECs.