A four-point bending apparatus is used to investigate the effects of stretching on collagen synthesis, mineralization and differentiation of osteoblasts. Cells are stretched at 1500 με for 24 hours. The responses of...A four-point bending apparatus is used to investigate the effects of stretching on collagen synthesis, mineralization and differentiation of osteoblasts. Cells are stretched at 1500 με for 24 hours. The responses of osteoblasts to mechanical signal of physiological stretching are evaluated from three aspects: collagen production, extracellular inorganic calcium secretion and ALP activity. The results show that osteoblasts decrease the collagen synthesis, calcium secretion and ALP activity compared to the control cells (65.82%,73.51%,48.10% respectively), confirming that cyclic stretching at 1500 με inhabits the physiological activity of osteoblasts.展开更多
In this contribution the influence of chemically synthesized magnetite particles coated by sodium oleate and PEG （MPEG）, and magnetosomes （MS） was gradually tested on the process of phagocytosis and the metabolic ...In this contribution the influence of chemically synthesized magnetite particles coated by sodium oleate and PEG （MPEG）, and magnetosomes （MS） was gradually tested on the process of phagocytosis and the metabolic activity （lysozyme and peroxidase activity） in leukocyte. Lysozyme activity is oxygen-independent liquidation mechanisms of engulfed microorganism, peroxidase activity is oxygen-dependent one. The both tested samples MS and MPEG lysed leukocyte cells during incubation. MPEG with concentration 10 and 20 μg/mL lysed almost all leukocytes and their cell viability was in the 14 ± 0.05% range. On the other hand, MS begin to influence leukocytes activity at the concentration of 1 μg/mL and this influence grows with increasing concentration up to 20 μg/mL. MS are more suitable for biological applications than MPEG which are more aggressive material than MS and their using is unavailable for these types of the test mainly for the concentration 10 - 20 μg/mL.展开更多
Objective： A new therapeutic strategy using nanocomposite scaffolds of grafted hydroxyapaUte （g-HA）/ poly（lactide-co-glycolide） （PLGA） carried with autologous mesenchymal stem cells （MSCs） and bone morphogene...Objective： A new therapeutic strategy using nanocomposite scaffolds of grafted hydroxyapaUte （g-HA）/ poly（lactide-co-glycolide） （PLGA） carried with autologous mesenchymal stem cells （MSCs） and bone morphogenetic protein-2 （BMP-2） was assessed for the therapy of critical bone defects. At the same time, tissue response and in vivo mineralization of tissue-engineered implants were investigated. Methods： A composite scaffold of PLGA and g-HA was fabricated by the solvent casting and particulate-leaching method. The tissue-engineered implants were prepared by seeding the scaffolds with autologous bone marrow MSCs in vitro. Then, mineralization and osteogenesis were ob- served by intramuscular implantation, as well as the repair of the critical radius defects in rabbits. Results： After eight weeks post-surgery, scanning electron microscopy （SEM） and energy dispersive X-ray spectroscopy （EDX） revealed that g-HNPLGA had a better interface of tissue response and higher mineralization than PLGA. Apatite particles were formed and varied both in macropores and micropores of g-HNPLGA. Computer radiographs and histological analysis revealed that there were more and more quickly formed new bone formations and better fusion in the bone defect areas of g-HNPLGA at 2-8 weeks post-surgery. Typical bone synostosis between the implant and bone tissue was found in g-HNPLGA, while only fibrous tissues formed in PLGA. Conclusions： The incorporation of g-HA mainly im- proved mineralization and bone formation compared with PLGA. The application of MSCs can enhance bone for- mation and mineralization in PLGA scaffolds compared with cell-free scaffolds. Furthermore, it can accelerate the absorption of scaffolds compared with composite scaffolds.展开更多
文摘A four-point bending apparatus is used to investigate the effects of stretching on collagen synthesis, mineralization and differentiation of osteoblasts. Cells are stretched at 1500 με for 24 hours. The responses of osteoblasts to mechanical signal of physiological stretching are evaluated from three aspects: collagen production, extracellular inorganic calcium secretion and ALP activity. The results show that osteoblasts decrease the collagen synthesis, calcium secretion and ALP activity compared to the control cells (65.82%,73.51%,48.10% respectively), confirming that cyclic stretching at 1500 με inhabits the physiological activity of osteoblasts.
文摘In this contribution the influence of chemically synthesized magnetite particles coated by sodium oleate and PEG （MPEG）, and magnetosomes （MS） was gradually tested on the process of phagocytosis and the metabolic activity （lysozyme and peroxidase activity） in leukocyte. Lysozyme activity is oxygen-independent liquidation mechanisms of engulfed microorganism, peroxidase activity is oxygen-dependent one. The both tested samples MS and MPEG lysed leukocyte cells during incubation. MPEG with concentration 10 and 20 μg/mL lysed almost all leukocytes and their cell viability was in the 14 ± 0.05% range. On the other hand, MS begin to influence leukocytes activity at the concentration of 1 μg/mL and this influence grows with increasing concentration up to 20 μg/mL. MS are more suitable for biological applications than MPEG which are more aggressive material than MS and their using is unavailable for these types of the test mainly for the concentration 10 - 20 μg/mL.
基金Project supported by the National Natural Science Foundation of China(Nos.51473164 and 51273195)the Joint Research Project of Chinese Academy of Sciences and Japan Society for the Promotion of Science(CAS-JSPS+1 种基金No.GJHZ1519)the International Science and Technology Cooperation Program of China(No.2014DFG52510)
文摘Objective： A new therapeutic strategy using nanocomposite scaffolds of grafted hydroxyapaUte （g-HA）/ poly（lactide-co-glycolide） （PLGA） carried with autologous mesenchymal stem cells （MSCs） and bone morphogenetic protein-2 （BMP-2） was assessed for the therapy of critical bone defects. At the same time, tissue response and in vivo mineralization of tissue-engineered implants were investigated. Methods： A composite scaffold of PLGA and g-HA was fabricated by the solvent casting and particulate-leaching method. The tissue-engineered implants were prepared by seeding the scaffolds with autologous bone marrow MSCs in vitro. Then, mineralization and osteogenesis were ob- served by intramuscular implantation, as well as the repair of the critical radius defects in rabbits. Results： After eight weeks post-surgery, scanning electron microscopy （SEM） and energy dispersive X-ray spectroscopy （EDX） revealed that g-HNPLGA had a better interface of tissue response and higher mineralization than PLGA. Apatite particles were formed and varied both in macropores and micropores of g-HNPLGA. Computer radiographs and histological analysis revealed that there were more and more quickly formed new bone formations and better fusion in the bone defect areas of g-HNPLGA at 2-8 weeks post-surgery. Typical bone synostosis between the implant and bone tissue was found in g-HNPLGA, while only fibrous tissues formed in PLGA. Conclusions： The incorporation of g-HA mainly im- proved mineralization and bone formation compared with PLGA. The application of MSCs can enhance bone for- mation and mineralization in PLGA scaffolds compared with cell-free scaffolds. Furthermore, it can accelerate the absorption of scaffolds compared with composite scaffolds.
