Objective: To study the effects of platelet-derived growth factor (PDGF) on the DNA content of the isolated osteoblast-like cells and the cellular period changes, and further study the effect of PDGF on bone fracture healing.
Methods: The cultured osteoblast-like cells in vitro were isolated from fetal rat calvaria and the effects of PDGF on cellular DNA contents were observed under flow cytometer. The changes of osteoblastic surface structure and ultrastructure were observed under electron microscope.
Results: PDGF could increase the DNA contents of cellular S period by promoting osteoblast from G0/G1 period into S period. The effects of PDGF on increasing cellular DNA contents were most significant at 24th culture hour (DNA content: 17.6% at the 24th hour, 9.0% at the 48th hour, 10.2% at the 72nd hour). PDGF could increase osteoblastic surface granules, reticular fibers and intracellular calcium salt crystals, and calcium granule mitochondria.
Conclusions: PDGF could promote bone fracture healing by stimulating osteoblastic DNA synthesis and cell proliferation. The flow cytometer is a better instrument to analyze cell DNA content for a large number of cells.