ABSTRACT
BACKGROUND:It is particularly important to search favorable scaffolds and seed cells in bone tissue engineering. However, no existing studies have reported the co-culture of adipose-derived stem cells and absorbable gelatin sponge. OBJECTIVE:To induce rabbit adipose-derived stem cells to osteoblasts, observe the adhesion, proliferation and biological characteristics of adipose-derived stem cells on absorbable gelatin sponge, and to provide experimental base for absorbable gelatin sponge as an effective carrier of fat stem cells transplantation in vivo. METHODS:Adipose-derived stem cells were cultured in vitro and identified with immunohistochemistry and flow cytometry. The passage 3 adipose-derived stem cells were induced to differentiate into osteoblasts and then seeded onto absorbable gelatin sponge after treatment with polylysine. The adhesion and proliferation of adipose-derived stem cells on scaffolds were observed under scanning electron microscope. RESULTS AND CONCLUSION:The rabbit adipose-derived stem cells were mainly round and oval shaped at 48 hours, and became long spindle shaped after 48 hours. Adipose-derived stem cells were positive for CD29 and CD44, and negative for CD33 and CD34. Adipose-derived stem cells can be induced to differentiate into osteoblasts after culture in the osteogenesis induced fluid for 72 hours. The induced osteoblasts that were co-cultured with absorbable gelatin sponge had an 85%adherence rate at 24 hours. The cells began to extend pseudopodium at 48 hours, and osteoblasts adhered in clumps and secreted a large amount of cellmatrix at 7 days. Absorbable gelatin sponge began to absorb and degrade. Experimental findings indicate that, adipose-derived stem cells have good histocompatibility with absorbable gelatin sponge, and absorbable gelatin sponge can be used as a biological carrier of adipose-derived stem cells.
ABSTRACT
BACKGROUND: Traditional methods of repairing bone defect such as autograft and allograft have some disadvantages that are hard to deal with, gene treatment may be a new approach. OBJECTIVE: To investigate the biological properties of cultured human osteoblasts transfected with vascular endothelial growth factor (VEGF) gene. DESIGN, TIME AND SETTING: A controlled experiment based on cytology was carried out in the Scientific Experiment Centre of Liaoning Medical College from May 2005 to May 2006. MATERIALS: Human lilac born block was harvested from a cervical spondylosis patient who required lilac bone graft with his informed consent of this patient. Plasmid pCDI/VEGF_(121) was given as gift from Professor Ma, Peking Unviersity Human Disease Genomics Research Center. Competent Escherichia coU was given as gift from Professor Liu, Liaoning Medical College. METHODS: Human osteoblasts were isolated and cultured in vitro. There were a VEGF transfection group and a control group in the experiement. Using cation liposome, the pCDINEGF_(121) eukaryotic expression plasmis was induced into human osteoblasts.MAIN OUTCOME MEASURES: At 1, 3, 5, 7 days following passage culture, the expression of VEGF in human osteoblasts was detected. Its effects on the call proliferation, the secretion of osteocalcin and alkaline phosphatase were investigated.RESULTS: After the plasmid pCDI-VEGF_(121) was transferred into human osteoblasts 3 and 7 days, VEGF mRNA expression was detectable by RT-CPR method. The call number of transfection group was larger than that of control group (P < 0.05 or P < 0.01).When the cells were cultured for 3 days, the positive rate of alkaline phosphatase in the transfection group was increased compared with control group (P < 0.01 ); the secretion of osteocalcin in the transfection group was higher than that of control group (P < 0.05 or P < 0.01 ).CONCLUSION: VEGF gene transfection can improve the proliferation and biological function of human osteoblasts cultured in vitro.
ABSTRACT
The treatment of avascular necrosis of the femoral head whose pathological procedure is femoral head avascularity and osteocyte necrosis induced by many etiological factors is one of the difficult subjects in orthopaedics. As a newly-developed technology, cytokines and gene therapy have been widely used in the research of avascular necrosis of the femoral head. Many cytokines and transduced genes have the effects of promoting vascular reconstruction and bone repairment so that it could recover the blood supply and repair the osteonecrosis of femoral heads. Most current researches remain in the experimental phase. Therefore, the research focus in the future comes down to the lengthening of gene transfection expression as well as the selection of vectors and tissue engineering bones that have low immunereaction and low toxicity.