Figure 2. In vitro assay of pcDNA-mOPG. (a) RT-PCR analysis of NIH3T3 cells. RT-PCR analysis was performed with cDNA from OPG-transfected NIH3T3 cells and control NIH3T3 cells. The results shown are from 1 representative independent experiment out of 3. C, control NIH3T3 cells; T, OPG-transfected NIH3T3 cells; L, DNA ladder. (b) Western blot analysis with antibody against OPG. L, protein ladder; Control, cell lysate from control NIH3T3 cells; Transfect, cell lysate from OPG-transfected NIH3T3 cells. The results shown are from 1 representative independent experiment out of 3. (c) Resorption assay (photos). Upper panel: Osteologic^® discs cultured with normal culture medium and 1,25-(OH)₂D₃. Lower panel: Osteologic^® discs cultured with 50% collected culture medium and 1,25-(OH)₂D₃. Arrowhead indicates resorption pit. The areas of the resorption pits from randomly selected fields were measured. The results shown are from 1 representative experiment out of 8. Bar = 100 µm. (d) Resorption assay (resorbed area of Osteologic^® discs). The areas of the resorption pits from randomly selected fields were measured. The resorbed areas of 24 fields were measured. * p < 0.05.