Figure 3

Role of Hif-1 and Hif-2 in dickkopf-related protein 2 and leptin expression during hypoxia. After following the RNA silencing protocol described in the Methods section, human osteoarthritis osteoblasts were incubated for 24 hours (RT-PCR experiments) to determine the expression of hypoxia-inducible factor 1 (Hif-1) (A), Hif-2 (B), dickkopf-related protein 2 (DKK2) (C) and leptin (D) (n =5 experiments), or for 48 hours to measure leptin production (E) (n =5 experiments), under hypoxia in the presence of 50 nM 1,25-dihydroxyvitamin D₃ (D3) or 0.1% EtOH. SiSrc, Scrambled silencing RNA (control). *P <0.05.