Effects of electromagnetic stimulation on gene expression of mesenchymal stem cells and repair of bone lesions

Objective: Most people experience bone damage and bone disorders during their lifetimes. The use of autografts is a suitable way for injury recovery and healing. Mesenchymal stem cells [MSCs] are key players in tissue engineering and regenerative medicine. Their proliferation potential and multipotent differentiation ability enable MSCs to be considered as appropriate cells for therapy and clinical applications. Differentiation of stem cells depends on their microenvironment and biophysical stimulations. The aim of this study is to analyze the effects of an electromagnetic field on osteogenic differentiation of stem cells

Materials and Methods: In this experimental animal study, we assessed the effects of the essential parameters of a pulsatile electromagnetic field on osteogenic differentiation. The main purpose was to identify an optimum electromagnetic field for osteogenesis induction. After isolating MSCs from male Wistar rats, passage-3 [P3] cells were exposed to an electromagnetic field that had an intensity of 0.2 millitesla [mT] and frequency of 15 Hz for 10 days. Flow cytometry analysis confirmed the mesenchymal identity of the isolated cells. Pulsatile electromagnetic field-stimulated cells were examined by immunocytochemistry and real-time polymerase chain reaction [PCR]

Results: Electromagnetic field stimulation alone motivated the expression of osteogenic genes. This stimulation was more effective when combined with osteogenic differentiation medium 6 hours per day for 10 days. For the in vivo study, an incision was made in the cranium of each animal, after which we implanted a collagen scaffold seeded with stimulated cells into the animals. Histological analysis revealed bone formation after 10 weeks of implantation

Conclusion: We have shown that the combined use of chemical factors and an electromagnetic field was more effective for inducing osteogenesis. These elements have synergistic effects and are beneficial for bone tissue engineering applications

Study of apoptosis inducing activity of calprotectin on fibroblast cell

One of the prominent types of connective tissue cells is fibroblast that synthesizes and maintains the extracellular matrix of many animal tissues. Previous studies illustrated that calprotectin protein has different cytotoxicity effects on fibroblast cells. Calprotectin is abundant in the mneutrophil cytosol; it has growth-inhibitory and apoptosis-inducing activities against various mcell types such mas tumor cells. The present study tries to introduce mechanism of growth inhibitory effect of calprotectin on human foreskin fibroblast cells [HFFF] and compare to etoposide [chemotherapy agent as control]. Calprotectin was purified from human neutrophil by chromatography methods. HFFF cell lines were used, maintained in RPMI 1640 medium supplemented with 10% FCS in a humidified incubator [37 degreeC and 5% CO2]. The HFFF cells were exposed to the different concentrations of calprotectin and etoposide for 24, 48 and 72 hours. Cell proliferation was assessed by using dimethylthiazol diphenyl tetrazolium bromide assay. Flow cytometric analysis was performed to evaluate the cytotoxic mechanism of calprotectin on HFFF cells. Our results revealed that calprotectin and etoposide induce growth inhibition of HFFF in dose- and time-dependent manners. Sensitivity of HFFF cells to cytotoxic effect of human calprotectin was highly remarkable. In addition, growth inhibitory effect of this cytotoxic agent mostly was governed through induction of apoptosis in the HFFF cells. Taken together, calprotectin not only has more potent anticancer activity in comparison with the etoposide, but it also is an apoptosis inducer that acts on the proliferation of normal cells like fibroblasts