Schwanns cells were obtained from the distal end of the sciatic nerve following Wallerian degeneration of SD rats. These cells were cultured with the anteriorhorn neuron of spinal cord of 14dayold SD rat fetus. The two kinds of cells were separated by a slice. Through the microscope, the dendrites and the morphology changes at the 24th, 48th, 72th, and 96 th hour after culture were observed. It was demonstrated that the Schwanns cells played the role of maintaining the survival of neuron and promoting the growth of dendrites. It was said that the Schwanns cells could secrete neurotrophic factor which made the body enlarged and caused the dendrites enlonged to several times of the body.
Schwanns cell (SC) was isolated from sciatic nerve of adult rat with Wallerine degeneration. After culture, SC-serum free culture media (SCSFCM) was obtained. By ultrafiltration with PM-10 Amicon Membrane, electrophoresis with DiscPAGE,and electrical wash-out with Biotrap apparatus, D-band protein was isolated from the SC-SFCM. The D-band protein in the concentration of 25ng/ml could affect the survival of the spinal anterior horn neuron in vitro, prominently and itsactivity was not changed after being frozen. The molecular weight of the protein ranged from 43 to 67 Kd. The D-band protein might be a neurotrophic substancedifferent from the known SCderived neurotrophic factors (NTF). Its concentration with biological activity was high enough to be detected. The advantages of MTT in assessment of NTF activity were also discussed.
The model of the denervated lateral head of gastrocnemius musde was adopted in this experiment on 50 rabbits. At random, the denervated muscle on oneside received the soleus muscle bundles with neurovascular pediele implantation (MBNPI). While the other side received the direct soleus nerve implantation (DNI). Eighteen weeks later after the two types of implantations the electromyography, force of muscles, histochmical findings and the electronic microscopic examination of the dernervated muscles of the two...
Objective To establish an animal model for repairing the sciatic nerve defect with a biodegradable poly D,L-lactic acid/nerve growth factor (PDLLA/NGF) that can control the release conduit in rats and to observe an effect of the conduit on the sciatic nerve regeneration. Methods The PDLLA conduit and the PDLLA/NGF-controlled release conduit (NGF 450 U per conduit) were madewith the solvent-volatilixation method. Forty male SD rats were randomly and equally divided into 4 groups. The middle segments (10 mm) of the sciatic nerves of the rats were excised and were then repaired with the sciatic nerve autograft(Group A), with the PDLLA conduit (Group B), with the PDLLA conduit and an injection of NGF (30 U) into the conduit (Group C), and with the PDLLA/NGF controlled-release conduit (Group D), respectively, with the 10-mm nerve defect left behind. Three months after operation, the morphologic parameters of the nerve regeneration were observed and evaluated under light microscope and electron microscope, and the image analysis was also made. Results Three months after operation, porous adherence between the conduit and the surrounding tissues could be observed. The conduit presented a partial biodegradation but still remainedintact in the outline and the proximal nerve regenerated through the conduit cavity. Based on the histological observation, the quantity, uniformity, and maturity of the nerve fiber regeneration in Groups A and D were better than those in Groups B and C. The image analysis indicated that there were no significant differences in the nerve fiber diameter, axon diameter or myelin thickness between Group A and Group D (P＞0.05). However, all the parameters in Groups A and D were better than those in Groups B and C (P＜0.05). Conclusion The PDLLA/NGF-controlled release conduit can effectively promote the sciatic nerve regeneration of rats. Its morphological index is similar to that of the nerve autograft.
Objective To introduce the cells and cell-transplantation methods for periodontal tissue engineering. Methods Recent l iterature about appl ication of cell-based therapy in periodontal tissue engineering was extensively reviewed, the cells and cell-transplantation methods were investigated. Results Mesenchymal stem cells were important cell resourcesfor periodontal tissue engineering, among which peridontal l igament stem cells were preferred. Bone marrow mesenchymal stem cells had several disadvantages in cl inical appl ication, and adipose-derived stem cells might be a promising alternative; different transplantation methods could all promote periodontal regeneration to some extent. Single-cell suspension injection could only promote a l ittle gingival regeneration, and tissue engineered scaffolds still needed some improvement to be used in periodontal regeneration, while cell sheet technique, with great cell loading abil ity and no need of scaffolds, could promote regeneration of cementum, periodontal l igament, and alveolar bone under different conditions. Conclusion Multipotent stem cells are fit to be used in periodontal tissue engineering; improvement of cell-transplantation methods will further promote periodontal regeneration.
Objective To explore the liver regeneration following partial liver transplantation. MethodsPartial liver transplantation in the rats were established, three experimental groups were: Ⅰ=control, partial liver resection; Ⅱ=orthotopic liver transplantation (OLT); Ⅲ=partial orthotopic liver transplantation (POLT). Liver function test, morphological investigations and liver regeneration were performed in different time after transplantation. The regenerative response of transplanted partial liver graft in rats were evaluated by Flow Cytometry and compared it to liver regeneration following resection.Results The serum concentrations of ALT, BILI increased in one week, but returned gradually to normal level within one month after transplantation. Large numbers of mononuclear cells infiltrating into the portal areas. Hepatocyte necrosis was observed on day 14 after transplantation. On day 30, the parenchyma cell showed a nearly normal appearance, bile duct proliferation was seen in portal areas. In addition, after liver resection and POLT some diploid hepatocytes were found. Dilation of the central veins, adjoining sinusoids and interlobar veins were seen in group Ⅲ. The partial liver graft is capable of regeneration similar to the situation following partial hepatectomy. The peak of liver regeneration was seen on day 1,2,4 following a hepatectomy and POLT and OLT, respectively.Conclusion The transplanted liver shows the same and/or enhanced regeneration compared to controls. There are several possible explanations for the slight delay in achieving the maximal regenerative response in rats undergoing the POLT and OLT. These may include damage that is induced by the operation itself, preservation, and reperfusion injuries. These suggest that this be caused by activation of the immune system and it might be related to the regulation of cytokines and hormone.
In order to observe the role of genetically modified Schwann cell (SC) with pSVP0Mcat in the regeneration of injured spinal cord, the cells were implanted into the spinal cord. Ninety SD rats were used to establish a model of hemi-transection of spinal cord at the level of T8, and were divided into three groups, randomly, that is, pSVP0Mcat modified SC implantation (Group A), SC implantation (Group B) and without cell implantation as control (Group C). After three months the presence of axonal regeneration of the injured spinal cord was examined by means of horseradish peroxidase (HRP) retrograde labelling technique and stereography. The results indicated that HRP labelled cells in Group A and B could be found in the superior region of injured spinal cord and the brain stem such as the red nuclei and oculomotor nuclei. The density of ventral hom neurons of the spinal cord and the number of myelinated axons in 100 microns of the white matter was A gt; B gt; C group. In brief, the pSVP0Mcat modified SC intraspinal implantation could promote regeneration of the injured spinal cord.
Objective To discuss peripheral nerve regeneration under immunosuppression. Methods Current research trends about relationship between peripheral nerve injury and immunoreaction, the experimental result of nerve regeneration after using various immunosuppressors, and the clinical findings after human allogenous hand transplantation were extensively reviewed. Results Peripheral nerve regeneration was accelerated under immunosuppression. Conclusion Peripheral nerve injury may induce immunoreaction, which inhibit nerve regeneration and function recovery.
Basing on the experimental results, 48 nerve defects (with the length of 3-4 cm in 21 cases, 4.1-5cm in 25 cases and 6cm in 2 cases) were repaired clinically by using vaseularized nerve sheath canal with living Schwann s cells, 87.5 percent of them obtained good results. The advantages were: (1) The neural sheath had rich blood supply with resultant less scar from its healing; (2) The living Schwann s cells would secrete somatomedin to promote the reproduction of neural tissues; and (3) The useless neurofib...
Objective To study the effects of the periosteum，synovium andcartilage tissues on the gene expressions of proteoglycan, collagen Ⅱ, andnuclear factor kappa B (NF-κB) and to investigate the different effects of these tissues on cartilage regeneration. Methods In 20 New Zealand white rabbits, 20 cartilage explants were taken from the knee joints in each rabbit, the sizeof which was 4 mm×4 mm×4 mm. All the cartilages were divided into the following 4 groups and cultured for 7 days: Group A, with 5 pieces (2 mm×2 mm) of the synovium of theknee joints in each dish; Group B, with 5 pieces (2 mm×2 mm) of the periosteum ineach dish; Group C, with 5 pieces (2 mm×2 mm×2 mm) of the cartilage in each dish; and Group D, with no addition of other tissues (control group). RNA was extracted from the cells of the cartilage explants (4 mm×4 mm×4 mm) in all the dishes. Thegene expressions of proteoglycan, collagen Ⅱ and NF-κB were defected by a reversetranscription-polymerase chain reaction (RT-PCR).Results In group A, the gene expression of proteoglycan was significantly decreased. The relative density of this gene expression had a significant difference when compared with that in group D (1.09±0.21 vs. 1.25±0.25, Plt;0.05); the gene expressions of collagen Ⅱ and NF-κB were also decreased, but they had no significant differences when compared with those in group D (Pgt;0.05). In groupB, the gene expressions of proteoglycan, collagen Ⅱ, and NF-κB were significantly increased. The relative densities of these gene expressions were 1.60±0.26, 1.57±0.24, and 4.20±2.22, respectively, which had significant differences when compared with those in group D (Plt;0.05). In group C, the relative density of the gene expression of collagen Ⅱ was 1.43±0.28, which had a significant difference when compared with that in group D (Plt;0.05), but therelative densities of the gene expressions of proteoglycan and NF-κB had no significant differences when compared with those in group D (Pgt;0.05). Conclusion The results indicate that the periosteum can up-regulate the gene expressions of proteoglycan, collagen Ⅱ and NF-κB. The NF-κB is likely to be an important nuclear transcription factor related to cartilage regeneration. The results also suggest that the periosteum maybe better in facilitating the cartilage repair and regeneration in clinical practice.