[Objective] To investigate the immigration and differentiation of neural stem cell in vivo after intravenous transplantation into adult rats with spinal cord injury.[Method]Lower ventricle tissue was obtained from new-born rats aged 14 to 16 days,and the target cells were identified after cultured in vitro,neural stem cells signed by Brdu was injected into model rats of full-cut spinal cord via tail vein one week after injury.CSEP test and BBB function evaluation were conducted 8 weeks later after transplantation.The specimens made from the injured spinal cord of rats were affused with 8% poly formaldehyde,which aimed to get pathology section and imunnohistochemical staining.[Result](1)According to BBB scores,functional recovery was found in injury group and transplantation group but did not reach normal level,while in transplantation group the functional recovers got the better.(2)cerebro-spinal evoked potential(CSEP)in control group and injury group disappeared,and the latency period of CSEP in transplantation group was prolonged,but control group was not interfered.(3)Compared with injury group,a large amount of Brdu positive cells existed at the injured part of spinal cord in the transplant group,which indicated that the engrafted NSCs could survive and migrate into the injured part,and some of them could differentiated into the glial fibriuary acidic protein(GFAP)and NF-200 positive cells that had characteristics of neuron or glial cell.[Conclusion]Neural stem cell can reach the injured part of spinal cord and replace the injured neuron or glial cell via intravenous transplantation,which enable the injured spinal cord to functionally recover to some extent.

Objective To develop novel polyetheretherketone(PEEK) based nanocomposites which possess the favorable antibacterial property,and to investigate the oral microbial adhesion and biofilm formation on the surfaces of PEEK,nano-fluorohydroxyapatite(n-FHA)-PEEK and nano-hydroxyaptite (n-HA)-PEEK.Methods The bacterial adhesion and biofilm formation on the surfaces of n-FHA-PEEK,n-HA-PEEK were investigated via microbial viability assay kit and laser scanning confocal microscope (LSCM),respectively,with pure PEEK as control group.Results No significantly statistical difference were found in the bacterial adhesion amounts on the surfaces of n-FHA-PEEK,n-HA-PEEK and PEEK at 1 h and 4 h.However,the number of bacteria on the n-FHA-PEEK surface decreased dramatically at 2 h(0.496±0.008) compared with n-HA-PEEK groups(0.543± 0.015,P＜0.01).Although the biofilms formation on surfaces observed by LSCM had similar morphology and thickness at 3,7,14 d,that on the n-FHA-PEEK surface showed the highest dead-to-live bacteria ratio among the three materials at 14 d.Conclusions The combination of n-HA,especially for the n-FHA could inhibit the bacteria adhesion and accelerate the bacterial death,eventually may have an influence on the structure of biofilms and reduce the risk of periimplantitis.Therefore,n-FHA-PEEK nanocomposites presented a good prospect for clinical applications as dental implant materials.

BACKGROUND: Bone tissue engineering based on pluripotent stem cells (PSCs) is a new approach to deal with bone defects. Protocols have been developed to generate osteoblasts from PSCs. However, the low efficiency of this process is still an important issue that needs to be resolved. Many studies have aimed to improve efficiency, but developing accurate methods to determine efficacy is also critical. Studies using pluripotency to estimate efficacy are rare. Telomerase is highly associated with pluripotency. METHODS: We have described a quantitative method to measure telomerase activity, telomeric repeat elongation assay based on quartz crystal microbalance (QCM). To investigate whether this method could be used to determine the efficiency of in vitro osteogenic differentiation based on pluripotency, we measured the pluripotency pattern of cultures through stemness gene expression, proliferation ability and telomerase activity, measured by QCM. RESULTS: We showed that the pluripotency pattern determined by QCM was similar to the patterns of proliferation ability and gene expression, which showed a slight upregulation at the late stages, within the context of the general downregulation tendency during differentiation. Additionally, a comprehensive gene expression pattern covering nearly every stage of differentiation was identified. CONCLUSION: Therefore, this assay may be powerful tools for determining the efficiency of differentiation systems based on pluripotency. In this study, we not only introduce a new method for determining efficiency based on pluripotency, but also provide more information about the characteristics of osteogenic differentiation which help facilitate future development of more efficient protocols.
Bone and Bones ; Down-Regulation ; Gene Expression ; In Vitro Techniques ; Methods ; Mouse Embryonic Stem Cells ; Osteoblasts ; Pluripotent Stem Cells* ; Quartz Crystal Microbalance Techniques ; Telomerase* ; Up-Regulation