An Investigation of the Simultaneous Effects of Bone Morphogenic Protein (BMP)-4 and Static Magnetic Field on Viability and Proliferation Rates of Rat Bone Marrow Stem Cells

This study investigated the possible synergistic effect of simultaneous treatment of bone morphogenic protein (BMP) -4 as a chemical stimulator and static magnetic field (SMF) as a physical stimulator on viability percent and proliferation rate in rat bone marrow stem cells. Passage 5 cells were trypsinized، and a cell suspension prepared after which the cells were counted and cultured in 25 cm2 flasks. Cells were incubated for one day and washed with phosphate-buffered saline. We added BMP-4 at the optimum concentration of 25 ng/ml at different times (24، 48 and 96 h) into the medium. The cells were exposed at an optimum intensity of 4 mT of the SMF at different exposure times (24، 48، and 96 h). Subsequently cells were washed with phosphate-buffered saline، trypsinized، and separate cell suspensions were prepared from each flask. We investigated the viability and proliferation rates of treated cells by staining them with Trypan blue and performed cell counts with an optical microscope. The mean numbers of whole cells and living cells were considered to be the proliferation and survival rates، respectively. Increased SMF exposure and BMP-4 increased the viability percent and change in proliferation rate in the treated groups compared with their corresponding controls. The maximum increased viability was observed in the group that was treated with BMP-4 for 96 h. Our results have supported the hypothesis that SMF alters the viability and proliferation rate of treated BMSCs، which was enhanced when the cells were treated simultaneously with SMF and BMP-4.