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Fig. 3 | Stem Cell Research & Therapy

Fig. 3

From: The effect of genetically modified platelet-derived growth factor-BB over-expressing mesenchymal stromal cells during core decompression for steroid-associated osteonecrosis of the femoral head in rabbits

Fig. 3

In vitro characterization of MSCs. a The proliferation rate of each cell type was evaluated by measuring the fold increase in dsDNA from day one, according to the PicoGreen dsDNA quantitation assay results. After three days of culturing, the PGK-PDGF-BB-MSCs demonstrated significantly greater proliferation than the unmodified MSCs (P < 0.001) and the CMV-PDGF-BB-MSCs (P < 0.05). After seven days of culturing, the PGK-PDGF-BB-MSCs demonstrated significantly greater proliferation than the unmodified MSCs and CMV-PDGF-BB-MSCs (P < 0.0001 for both). The CMV-PDGF-BB-MSCs also demonstrated greater proliferation than the unmodified MSCs (P < 0.01). b Expression level of PDGF-BB was measured by ELISA and normalized by the amount of dsDNA present for each cell type. Expression of PDGF-BB by the unmodified MSCs was undetectable. After three and seven days of culturing, the CMV-PDGF-BB-MSCs exhibited significantly greater expression of PDGF-BB than the PGK-PDGF-BB-MSCs (P < 0.0001 and P < 0.01, respectively). Osteogenic differentiation capacity of each cell type was assessed by staining for (c, e) ALP and with (d, f) Alizarin Red and normalizing by the amount of dsDNA that was present for each cell type on day one. After 14 days of culturing, PGK-PDGF-BB-MSCs demonstrated greater staining for ALP than unmodified MSCs (P < 0.0001) and CMV-PDGF-BB-MSCs (P < 0.05). Additionally, CMV-PDGF-BB-MSCs demonstrated greater staining than the unmodified MSCs (P < 0.0001). After 28 days of culturing, PGK-PDGF-BB-MSCs demonstrated a trend towards greater staining than the CMV-PDGF-BB-MSCs (P = 0.072). PDGF-BB platelet-derived growth factor-BB, MSCs mesenchymal stromal cells, CMV-PDGF-BB-MSCs genetically modified cytomegalovirus promoter PDGF-BB over-expressing MSCs, PGK-PDGF-BB-MSCs genetically modified phosphoglycerate kinase promoter PDGF-BB over-expressing MSCs; dsDNA double-stranded DNA, ELISA enzyme linked immunosorbent assay, ALP alkaline phosphatase. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001

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