(A) SIRT1 mRNA and protein abundance was determined in H9c2 cells treated with normoxia (room air, ~20% O2) or hypoxia (1% O2) for 24 hours. Data are mean ± SEM. n = 4 *P < 0.05, hypoxia versus normoxia. (B) Primary cardiomyocytes were isolated from E21 fetuses and treated with normoxia (room air, ~20% O2) or hypoxia (1% O2) for 24 hours. SIRT1 mRNA and protein abundance was determined. Data are mean ± SEM. n = 5 *P < 0.05, hypoxia versus normoxia. (C) H9c2 cells were transfected with miR133a-LNA or the negative control (NC) for 48 hours followed by the treatment of normoxia or hypoxia (1% O2) for 24 hours. SIRT1 protein abundance was determined. Data are mean ± SEM. n = 4 *P < 0.05, hypoxia versus normoxia.