| As the aging of the Chinese population accelerations, the clinical repairing of bone defects will face huge challenges. At present, the large-scale bone defect mainly takes the repairing using auto-graft bone as the ―golden standard‖. However, the resources of auto-graft bone are very limited, which restricts its development. The allograft bone and hetero-graft bone will cause immunological rejections, leading to inflammations and greatly increasing risks such as infections. In recent years, the developments of tissue engineering have provided a new method for large-scale bone defect. The principle of tissue engineering is combine cells and scaffolds to construct engineered tissues or organs similar to the body’s tissues in structure and function.As BMSCs having a stable resource and the convenience of gaining, they can differentiate towards various kinds of cells under certain induction conditions. BMSCs are the ideal seed cells for bone tissue engineering. The ideal bone scaffolds of tissue engineering must have good biological compatibility, the feature of being able to be processed, degradable and harmless to the body, and appropriate mechanical property, which cannot be met by a single kind of material. Hydroxyapatite(HA) has a good biological compatibility and bone conductivity. The material of poly caprolactone(PCL) has a good mechanical property and degradable property. There maybe exist a wide application in producing the composite bone scaffolds by combining HA and PCL. How to maintain the viability of BMSCs cultured in the scaffolds is the key point to clinical trials of bone tissue engineering and also is the hot spots of tissue engineering.PEMF, a high-energy non-ionizing radiation,, has been applied to the clinic as a non-inclusive physical therapy and achieved substantial curative effects in the orthopedic diseases such as repairing bone injuries and treating osteoporosis. Previous studies have showed that PEMF not only increased the proliferation and differentiation of osteblasts but also improved the microenvironment of bone cells when they were used to treat the bone related disease. However, it is still unclear whether PEMF can increase cell viability of rat BMSCs cultured in two-dimension and three dimensional scaffolds.Objective: The aim of this study is to investigate the effect of PEMF on cell proliferation and differentiation of rat BMSCs cultured in two-dimension and the effect of PEMF on cell viability, morphology, proliferation as well as differentiation of BMSCs cultured in scaffolds. We hope establish a quick, safe and effective strategy for the cell proliferation of bone tissue engineering.Method: 1. BMSCs derived from SD rats, were cultured. BMSCs were identified by using osteogenic and adipogenic induction. 2. HA/PLC scaffolds were prepared by double-layer salting method. BMSCs were cultured on the HA/PCL scaffolds up to 14 days. Cellular responses in terms of cell adhesion, proliferation, ALP activity were investigated. 3. Different strength and treatment time of PEMF were used to stimulate the BMSCs and the proliferation and differentiation of cells were examined. 4. BMSCs cultured on the HA/PCL scaffolds were treated by PEMF up to 21 days. Cellular responses in terms of cell adhesion, viability, proliferation, differentiation were investigated.Results: 1. BMSCs derived from SD rats are spindle-shaped appearance and can be induced to form osteogenesis and adipogenesis. 2. It can be seen that the HA/PLC scaffolds prepared by double-layer salting method have a high porosity and a good connectivity between pores. This scaffolds supported BMSCs adhesion, viability and proliferation. 3. PEMF with the frequency of 15 Hz, the strength of 1mT could significantly promote the proliferation of BMSCs at 4d, 7d(p<0.05) and cell differentiation at 14d(p<0.05). 4. PEMF(15Hz、1mT) not only significantly increased the proliferation, ALP activity, and mineralized nodules of BMSCs cultured in HA/PCL scaffolds but also maintained cell viability of BMSCs in the scaffolds.Conclusion: PEMF with the frequency of 15 Hz and the strength of 1m T treatment not only significantly increased the proliferation and ALP activity of BMSCs cultured in two-dimension, but also maintained cell viability and cytoskeleton structure of BMSCs in the scaffolds as well as promoted the proliferation, ALP activity, and mineralized nodules of BMSCs cultured in HA/PCL scaffolds. This study has potential significance not only for establishment a quick, safe and effective strategy for the cell proliferation of bone tissue engineering, but also for our understanding the bioeffect of electromagnetic fields. |
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