The effects of pulsed electromagnetic field on the functions of osteoblasts on implant surfaces with different topographies.

The use of pulsed electromagnetic fields (PEMFs) is a promising approach to promote osteogenesis. However, few studies have reported the effects of this technique on the osseointegration of endosseous implants, especially with regard to different implant topographies. We focused on how the initial interaction between cells and the titanium surface is enhanced by a PEMF and the possible regulatory mechanisms in this study. Rat osteoblasts were cultured on three types of titanium surfaces (Flat, Micro and Nano) under PEMF stimulation or control conditions. Protein adsorption was significantly increased by the PEMF. The number of osteoblasts attached to the surfaces in the PEMF group was substantially greater than that in the control group after 1.5h incubation. PEMF stimulation oriented the osteoblasts perpendicular to the electromagnetic field lines and increased the number of microfilaments and pseudopodia formed by the osteoblasts. The cell proliferation on the implant surfaces was significantly promoted by the PEMF. Significantly increased extracellular matrix mineralization nodules were observed under PEMF stimulation. The expression of osteogenesis-related genes, including BMP-2, OCN, Col-1,ALP, Runx2 and OSX, were up-regulated on all the surfaces by PEMF stimulation. Our findings suggest that PEMFs enhance the osteoblast compatibility on titanium surfaces but to different extents with regard to implant surface topographies. The use of PEMFs might be a potential adjuvant treatment for improving the osseointegration process.