| Spinal cord injury (SCI) is a serious public health problem all over the world. Severe SCI even can lead to lifelong paralysis, which brings the patients immense suffering and places a heavy burden on their family members and society. Accounts of the treatment of SCI date back to ancient times. Despite tremendous progress in the battle against SCI, the results were not entirely satisfactory. The high-dosage glucocorticoid treatment was once considered a milestone in the treatment of spinal cord injuries. With its wide clinical application, however, the disadvantages of the treatment gradually became obvious, involving a variety of complications (e.g. gastrointestinal hemorrhage), the high expenses for treatment and the strict time limit during treatment, which hindered its further application. Acute high dosagee glucocorticoid and surgical decompression are the widely adopted therapies at present. In recent years, the discovery of neural stem cells and the research on stem cell transplantation brought new hope for an improvement of the treatment of spinal cord injury. However, the problems related to stem cell transplantation, such as ethical issues, the long-term use of in-vitro amplification, and the potential risk of oncogenic tumorigenesis, limit the wide application of the therapy.Vitamin C is one of the essential substances in human bodies, which plays an important role in daily metabolism of human bodies. Recent studies have showed that Vitamin C plays an important role in the treatment of a variety of nervous system diseases. In particular there are good therapeutic effects of high-dosages of Vitamin C on the neurodevelopmental defects. The present experimental study focused on high-dosages of Vitamin C for recovery after spinal cord injury.The axonal fracture in the site of injury after spinal cord injury impairs the conduction by nerve fibers, which hence damages the feeling of movement segments and causes autonomic dysfunction. The distal end of an axonal fracture later degenerates and disappears, while retrogression cataplasia occurs at its proximal end. A series of secondary injuries can occur after spinal cord injury which lead to the death of a large number of ST segment cells with axon progressive degeneration and necrosis. The subsequent glial scars hinder regeneration of axons and nerve function recovery. However, further observation in spinal cord injury has found that spinal cord axon regeneration after injury is not lost. Regeneration can occur up until the edge of the fractured injured section, but cannot progress through the damaged area to achieve full recovery. Therefore, the focus of this study was on how to assist the axon regeneration through the damaged area.Neural scaffolding material was developed by this project with a directional micro-tubular structure. It can prevent a scar from growing, and can provide regenerative axons with a directional micro-tubular structure, which promotes the regenerated axons to reach a remote target for the recovery from spinal cord injury.Bone marrow mesenchymal stem cells (BMSC) is a pluripotent stem cell line with the ability of differentiating to terminal tissue cells. Much attention is being paid to BMSC in tissue engineering research. Compared with other sources of stem cells, bone marrow stromal cells have the following characteristics including extensive sources and easy to implement autologous transplantation, which leads to wide clinical use. Therefore, this study used bone marrow stem cells as seed cells, together with new scaffolding material in an experimental model of spinal cord injury.Part one: Research in employment of high-dosage Vitamin C treatment for spinal cord injury[Objectives] To confirm the efficacy of large dosages of vitamin C for the treatment of spinal cord injury[Methods] We used the Rat Dorso-ASCI Model, with the adoption of impactor instrument"Impactor Model I"according to the modified Allen's Method 30 SD rats were randomly divided into three groups:Group1 the control group Provided with normal saline after surgery;Group2 the Normal-Dosage -Vitamin-C Treatment Group (NDVCT Group); Provided with daily intraperitoneal injection of 100mg/kg Vitamin C for 4 weeks after the operation;Group3 the High-Dosage-Vitamin-C-Treatment Group (HDVCT Group); Provided with a dosage of 200mg/kg per day vitamin C.On the 7th, 14th, 21st, 28th day after the operation, BBB assessment and footprint analysis were performed for each group;On the 28th day after surgery, all rats were sacrificed. Then sections were made for HE staining and histological examination to determine the extent of cavitation in the damaged region.[Results] Behavioral assessment of the HDVCT Group appeared to be better than that of the control group.BBB Assessment:On the 14th day, the BBB score in the HDVCT Group was significantly higher (10.50±1.08 VS 7.10±0.86, P <0.05) than that in the control group. There was no significant difference between the HDVCT Group and the NDVC Group, and no significant difference between the NDVC Group and the control group (P> 0.05).Footprint Analysis:On the 14th day, the step stride length in the HDVCT Group was significantly longer (11.80±1.32 VS 10.11±0.95, P <0.05) than that in the control group. The step width stride width in the HDVCT Group was significantly smaller (4.85±0.46 VS 5.63±0.38, P <0.05) than that in the control group.Histological Observation:The cavitation area of the damaged zone in the HDVCT Group was significantly less than that in the control group (4.85±0.46 VS 6.12±0.38, P <0.05).Part two: Culture of Bone Marrow Stromal Stem Cells [Objectives] To develop highly pure and differentiative bone marrow stromal cells.[Methods] The method of modified bone hol-marrow adherent incubation was used to induce the BMSC to differentiate to sclerotomal cells and fat cells, followed by flow cytometry to determine the induction of differentiation in the BMSC surface antigens.[Results] The steadily growing BMSC was cultured. Induced by the corresponding inducer, the BMSC cells differentiated to sclerotomal cell and fat cells with the characteristics of sclerotomal cell and fat cells. The detection of cell surface antigens by flow cytometry found that all the cells were homogeneous: CD29, CD90, CD44 were expressed as 99.62%, 99.75%, 99.02% respectively, and CD45, CD34, as 2.40%, 2.99% respectively.Part three: The combination of new scaffolding materials, bone marrow stem cells and HDVC treatment in spinal cord injury[Objectives] To evaluate the efficiency of the combination of new scaffolding material and bone marrow stem cells in spinal cord injury; To evaluate the efficiency of HDVC treatment in spinal cord injury.[Methods] The efficiency of the combination of new scaffolding materials and bone marrow stem cells with HDVC treatment was experimentally determined in spinal cord injury, using immunohistochemistry, nerve electrophysiology, retrograde-labelling techniques and behavior determination methods.[Results] Morphological observations showed that the connections between some nerve fibers in the spinal cord damaged area could be seen at 12 weeks after transplantation. Using retrograde tracing, the anterior horn of the spinal cord and dorsal root ganglia could be detected as fluorescent gold labelling positive neurons.Behavior evaluation showed that: the group with scaffolding material and bone marrow stem cells was better than that in the control group, and there was no significant difference between the HDVCT group and the group with scaffolding materials and bone marrow stem cells.
|
PDF Full Text Request