Figure 2. Nampt promoted osteogenic differentiation. (A) MC3T3-E1 cells were transfected with adenoviruses. GFP marker genes were detected 48 h after transfection under both bright field and fluorescence microscopy (100×). (B) Real-time PCR analysis showing Nampt gene expression normalized to β-actin and (C) Western blot results showing the protein expression of Nampt 3 days after the transfection. On the 7th d of culture in OBM, (D) ALP staining and (E) Measurement of ALP activity showing that ALP was decreased in sh-Nampt cells and increased in ad-Nampt cells. (F) Western blot results showing the protein expression of Sirt1, Runx2, Col1a1 and OCN. Con (control) cells were not transfected; sh-con and ad-con (negative control) cells were transfected with nontargeting control viruses; sh-Nampt cells were transfected with Nampt knockdown shRNA; ad-Nampt cells were transfected with vector over expressing Nampt. The data are expressed as the mean ± SD. *, p<0.05; **, p<0.01.