| This dissertation could be divided into three parts. There are the fabrication of a novel nerve tissue engineering scaffold and its application in the treatment of spinal cord and peripheral nerve segmental injury.Part I Fabrication of a novel nerve tissue engineering scaffold and the research of its correspondingcharacteristics.Spinal cord injury (SCI)and peripheral nerve defect are the worldwide questions that still puzzle the surgeons. Most researchers have pin their hope on nerve tissue engineering research, in which the most difficult point is lacking the ideal tissue engineering scaffold. The component of the scaffold is oneof the important parameter. The component of the ideal scaffold should be quite similar to that of the extracellular matrix (ECM) synthesized and secreted by neurons. The bridging tissue-engineering scaffold produced from natural ECM materials, containing elements and three dimensional structure that is needed by nerve regeneration. This kind of scaffold has no immunogenity and could effectively promote the regeneration of axon. Type I and IV collagen, heparan sulfate in the nerve ECM have draw much attention because of their distinct character.Ideal scaffold should have similar inner structure to that of the nerve. This would be beneficial to the regeneration of the nerve, because the regeneration of the nerve has its own special request. The growth of the axon is different from that of the other tissues. The growth of axon must be directional so that to recover the function of the extremity in the most extent. Nerve tissue engineering scaffold used before has no regular directional inner tunnel. When it is implanted, the irregular tunnel would hinder the growth of the axon. On the other hand, the seed cells could only be attached to the surface of the scaffold or limited superficial tunnels, which could not effectively direct the directional growth of the axon. So we suggest that if the nerve repairing material has axial arranged tunnels, this would be beneficial to the directional growth of the axon, so that the injured nerve could be repaired and regenerated effectively.In this research, type I and IV collagen, heparan sulfate were used to produce nerve tissue engineering scaffold for the first time. 1. Collagen and heparan sulfate were dissolved in 0.05mol/L acetic acid and mixed into gel like liquid and was injected into silica gel model. The silica gel model was then dipped into liquid nitrogen at the temperature -180C with the speed 2x10-5m/s-1 and was frozen into a cylinder, which was freeze-dried. Proteins in the model were cross-linked by ultraviolet radiation. The scaffold then was produced. The scaffold was observed through electron microscope and the internal structure compared with that of the peripheral nerve and the spinal cord for any difference. The diameter of the microtubule inside the scaffold was analyzed by computer. 2. Hoechst33342 labeled Schwann cells were implanted into the collagen-heparan sulfate scaffold. The space arrangement of Schwann cells in the scaffold was observed by fluorescence microscope and scanning electron microscope. 3. 10mm collagen-heparan sulfate scaffold was transplanted to repair the rat sciatic nerve defect. Specimens were acquired in the first group at 3,5,7 and 14 days after operation. Immunofluorescence staining was applied to detect the expression of bFGF, NGF and S100 in the scaffold. In the second group, Evens blue was perfused into the vessels through femoral vein at the 3, 5, 7 and 14 days after the operation. Vascular VIII factor was immunofluorescence stained to observe the growth ofvessels into the scaffold. Parts of the specimens were also observed by transmission electron microscope. 4. Trypan blue staining and MTT method were used to detect the bioactivity of Schwann cells and olfactory ensheathing cells when they were co-cultured with collagen-heparan sulfate scaffold.Result : 1. Collagen-heparan sulfate scaffold produced by freeze-dry technique has longitudinal, parallel arranged micr...
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