Papers by Keyword: Nerve Regeneration

Abstract: One of the major challenges in the development of scaffold for nerve regeneration is enhancing mechanical strength of the material to avoid the scaffold to rapidly degrade during regeneration process in nerve system. The aim of this study was to reveal the effect of freeze-thaw to the properties of gelatin-carbonated hydroxy apatite (CHA) membrane in two ratios 7 to 3 and 6 to 4 for gelatin to CHA respectively. Some variations of freeze-thaw cycles were applied for both ratios, which is referred for its biocompatibility in cells.The CHA was synthesized by wet precipitating method of calcium hydroxide and phosphoric acid in gelatin solution at room temperature and open system. The X-Ray Diffraction (XRD) and FTIR analysis was conducted to confirm the formation of type-B CHA in gelatin matrix. The resulted membrane was then subject for membrane characterization.It was known from the study that freeze-thaw treatment during membrane fabrication affects several properties of the membrane. Platelet loading capability decreased when freeze-thaw cycles increased. Meanwhile, the platelet was released more rapidly by freeze-thawed gelatin-CHA membrane compared to non-freeze-thawed one. The degradation percentage of the membrane decreased with the increasing freeze-thaw cycles, showing 4 hours slower degradation in the freeze-thawed membrane compared to the unfreeze-thawed one.Furthermore, it was observed that freeze-thaw improved the tensile strength of the membrane and the modulus elasticity increased simultaneously. Moreover, in general it was observed from this study that freeze-thaw treatment did not affect permeability of the membranes towards glucose transport.

Abstract: Introduction: Peripheral nerve injury is common in clinical practice. Nerve defect is a challenging scenario. The current gold standard of managing a nerve defect is autologous nerve graft. However, due to the selection of nerve graft and donor site morbidity, artificial nerve conduits are gaining popularity. However, there are drawbacks of single hollow conduit such as lack of internal support to prevent conduit collapse and inability so as to recreate the proper native spatial arrangement of cells and extracellular matrix within the conduit. In this study, the biocompatibility and efficacy of five-channel and eight-channel Crosslinked Urethane-doped Polyester Elastomers (CUPEs) as nerve guidance conduit will be evaluated through a rat model with reconstruction of segmental peripheral nerve defect. Material and Method: Eighteen adult Sprague-Dawley rats were used. They were randomly allocated to three groups: autograft group, five-channel conduit group and eight-channel conduit group with each consisted of six rats. A 10mm nerve defects were created at the right sciatic nerve. They were bridged with reverse autograft, 5-channel conduit and 8-channel conduit. After eight weeks the rats were euthanized and the reconstructed nerves were harvested for histomorphometric analysis. Result: All conduits showed regenerated nerve tissue inside. There was no collapse of the conduits. There were no severe tissue reaction or scarring near the reconstructed nerve. No neuroma was formed. Histomorphometric analysis showed nerve regeneration was enhanced with increasing number of channels inside conduit. There was overall drop in fiber density between proximal and distal segment among all groups. Conclusion: CUPE nerve guidance conduit is biocompatible and shows good nerve regeneration in reconstructing nerve defect.

Abstract: Preliminary investigations have demonstrated that silicon oxides are capable for living cells adsorption. We used this capacity to regenerate nerve fibers. Different kinds of silicon oxides grown on silicon nanowires with different diameters in the range of 100 to 1000 nm were used for preparation of implants. Regeneration of nerve fibers was studied on sciatic nerves. Experiments were carried out in vivo on several groups of Whistar rats. After transverse sectioning the nerve of the first group of rats we injected the implant between the distal and the proximal nerve stumps and then repaired the injury with epineural sutures. The rats from the second (reference) group were operated in the same manner but without injecting the implants or even without transverse sectioning of the nerve fibers (sham-operated animals). The functionality of the rats` legs was monitored after six weeks. After that the nerves were prepared for examination by TEM (Transmittance electron microscopy). The main conclusion from the experiments is that the implants of oxidized silicon nanowires enhance the growth of new nerve fibers and are therefore promising for the nerve regeneration. In this report, the peculiarities of the nerve regeneration as well as the prospects of the nerve impulse transmission along the silicon nanowires are discussed.

Abstract: The treatment of peripheral nerve injuries is still one of the most challenging tasks in neurosurgery, as functional recovery is rarely satisfactory in these patients. The concept behind the use of biodegradable nerve guides is that no foreign material should be left in place after the device has fulfilled its task, so as to spare a second surgical intervention. In a previous study, flexible and biodegradable chitosan-γ-glycidoxypropyltrimethoxysilane (GPTMS) hybrid membranes exhibited better cytocompatibility in terms of osteoblastic cells than chitosan membrane. Porous chitosan hybrid membranes, derived by freeze-drying the hybrid gels, showed that the cells were attached and proliferated both on the surface and into pores. The aim of the present study was to evaluate the influence of these chitosan hybrid membranes in terms of their inflammatory response and remodeling of connective tissue during wound-healing processes before use as a periphery nerve graft. The porous chitosan hybrid membranes showed good biocompatibility and improved posttraumatic axonal regrowth and functional recovery.

Abstract: In nerve tissue engineering, scaffolds act as carriers for cells and biochemical factors and as constructs providing appropriate mechanical conditions. During nerve regeneration, new tissue grows into the scaffolds, which degrade gradually. To optimize this process, researchers must study and analyze various morphological and structural features of the scaffolds, the ingrowth of nerve tissue, and scaffold degradation. Therefore, visualization of the scaffolds as well as the generated nerve tissue is essential, yet challenging Visualization techniques currently used in nerve tissue engineering include electron microscopy, confocal laser scanning microscopy (CLSM), and micro-computed tomography (micro-CT or μCT). Synchrotron-based micro-CT (SRμCT) is an emerging and promising technique, drawing considerable recent attention. Here, we review typical applications of these visualization techniques in nerve tissue engineering. The promise, feasibility, and challenges of SRμCT as a visualization technique applied to nerve tissue engineering are also discussed.

Abstract: Sensory perception thresholds of implants were much higher than those of natural teeth. The purpose of this study was to evaluate the biocompatibility of TiO2/HA-biocoated dental implants for nerve regeneration using cultured Schwann cells. The nano-TiO2/HA composite bioceramic coating was developed on the surfaces of commercially pure titanium discs by sol-gel route, and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Using smooth titanium discs as a control, Schwann cell responses to the coating were evaluated by SEM, MTT assay, total protein content and leakage of cytosolic lactate dehydrogenase (LDH) activity. In addition, the amount of brain-derived neurotrophic factor (BDNF) secreted by Schwann cells was measured by Enzyme-Linked Immunosorbent Assay (ELISA). It was observed that the coating had fine crystallites and homogeneous micropores in the diameter of 5-10 um. The cell morphology, proliferation and function were unaffected. The results indicate that the TiO2/HA bioceramic coating developed on the surface of pure titanium by sol-gel route had good biocompatibility with Schwann cells for nerve regeneration around dental implants.