| Summary: | 碩士 === 國立臺北科技大學 === 生物科技研究所 === 97 === Low-frequency Pulsed Electromagnetic Field (EMF) has been proved by the FDA to be used in clinical applications to treat non-union bone fractures and to release pain. Bone defects over the size of 1cm usually can’t be repaired by EMF alone and requires the used of tissue engineered scaffolds. Implanting osteogenic porous scaffolds can induce bone cell growth and promote tissue repair. However, surgical processes cause inflammatory reactions and macrophages, one of the non-specific inflammatory cells, are known to bring in fibroblast cells to the surgical sites. Fibrous tissue around implants can impede implant/tissue integration and compromise the function of implant later.
We propose to study the effects of EMF on the behaviours of macrophages during inflammation and how the effects influence the subsequent bone repair. Bone cells (7F2 osteoblast) were seeded on chitosan porous scaffolds and co-cultured with macrophage (raw264.7). Lipopolysaccharide was added to the culture medium to induce macrophage to release NO and inflammatory cytokines. The co-culture was exposed to electromagnetic field (18-30 Gauss, 75Hz, impulse width 1.3 ms) for 9 hours. Immediately and seven days after EMF exposure, osteoblast cell viability, proliferation, gene expressions (type I collagen, osteocalcin), ALP activity were measured. NO release from macrophage were measured as well.
Our results showed the concentrations of NO were lower in control than the EMF group at both time points. Osteoblasts in the EMF group had higher proliferation rate and cell viability but lower ALP activity compared to the control group. The results showed that thought EMF did not suppress the inflammatory reactions of macrophages in the co-culture, it did accelerate growth and maturation of osteoblasts with the presence of inflammatory factors. The in vivo effects of EMF suppressing pain and inflammation may not begin with macrophages but other physiological pathways.
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