Vascularization-promoting allogeneic nerve repair material and preparation method thereof

Abstract

The invention discloses a method for promoting vascularization of an allogeneic nerve repair material, and belongs to the field of peripheral nerve repair materials. The vascularization-promoting allogeneic nerve repair material is based on an acellular allogeneic nerve, and an astragalus polysaccharide alginic acid sustained-release microcapsule is compounded on the surface of the acellular allogeneic nerve. The decellularized allogeneic nerve is degreased and decellularized in a physical mode, and antigen components are effectively removed; the astragalus polysaccharide is a natural extract from tonifying traditional Chinese medicine astragalus, and compared with an angiogenesis factor, the astragalus polysaccharide has the advantages of no tumorigenicity, stable activity, low price and the like. The vascularization-promoting allogeneic nerve repair material disclosed by the invention can solve the problem of insufficient cell and nutrition supply caused by slow vascularization after allogeneic nerve implantation, and promotes nerve repair.

Description

Technical Field

[0001] The invention belongs to the field of nerve repair materials for neurosurgery to treat peripheral nerve defects, and in particular relates to an allogeneic nerve repair material capable of promoting vascularization of nerve grafts and a preparation method thereof. Background Art

[0002] Autologous nerve transplantation is the "gold standard" for the clinical treatment of peripheral nerve defects and repair. However, due to its limited source, autologous nerve transplantation cannot meet the needs of repairing larger and extensive nerve defects, and it increases surgical trauma and causes dysfunction of the donor site. Although biological materials such as autologous skeletal muscle and vein and synthetic materials such as silicone tubes can guide nerve regeneration, their structure is different from the neural basement membrane, axon regeneration is poor, and the distance for repairing nerve defects is limited, so their clinical application value is limited. Allogeneic nerves have become the focus of research by scholars in recent years because of their wide source of raw materials and easy access. However, allogeneic nerve transplantation is still in the experimental research stage and is still a long way from complete repair.

[0003] A successful nerve transplant should have the following characteristics: (1) the regenerated axons must be able to grow into and reach the distal site through the transplant; (2) low antigenicity; (3) rapid blood supply. However, allogeneic nerves are highly antigenic, which can induce immune rejection and damage the nerve structure, causing the basement membrane tube to collapse, hindering nerve regeneration. Therefore, allogeneic nerve transplantation must deal with the problem of host immune rejection. In previous studies, it was believed that the peripheral nervous system was an immune-privileged area due to the presence of the blood-nerve barrier. However, recent studies at home and abroad have shown that the peripheral nervous system is not an immune-privileged area. Schwann cells are the main target of the host immune response, among which myelin is the main part that causes rejection. The collagen components of the triple membrane structure of the nerve and the basal lamina of the Schwann cells are not the main antigenic components of the nerve. There are various fixative factors in the allogeneic nerve matrix that promote neuronal growth. When peripheral nerves regenerate, there are receptors for these factors on the surface of the growth cone of the nerve axon, which can promote the growth of the nerve axon. Therefore, effective decellularization and antigen removal of allogeneic nerves is one of the key factors in preparation.

[0004] The main structure of peripheral nerve trunk is composed of nerve fiber bundles and their surrounding connective tissue including blood vessels. After nerve transplantation, there are roughly two forms of revascularization of the transplanted nerve segment: (1) intraneural form, i.e., internal plexiform blood vessels, which can last for 24 weeks; (2) extraneural form, i.e., external longitudinal blood vessels, which appear within 3 to 6 weeks after transplantation. Studies have shown that nerves without blood vessels are in an ischemic state within 3 days after transplantation, and blood flow begins to increase sharply around 1 week; while blood flow increases in the early stage after transplantation of vascularized nerves, but is basically in a stable state, which is of certain significance for maintaining the stability of the peripheral nerve microenvironment. The local microenvironment and various nutrients required for nerve regeneration are very important for the repair and regeneration of peripheral nerves, and these are all closely related to local blood supply. Early vascularization of nerve grafts can provide sufficient nutrition for various transplanted cells, thereby promoting axon growth and nerve regeneration; on the other hand, it can reduce the formation of collagen fibers in the body, facilitating the passage of new axons. In addition, the early vascularization of nerve grafts can also gather macrophages from the blood, which is conducive to the rapid removal of various degenerative products of axons and myelin sheaths after peripheral nerve injury, thereby providing a good channel for the growth of new axons to the distal end.

[0005] Insufficient vascularization is a key factor that restricts the success of nerve defect repair. The failure of peripheral nerve grafts to vascularize early and establish blood circulation in the body early restricts their further clinical application. Studies have shown that cells can only survive through diffusion within 150 to 200 μm around blood vessels, otherwise it will be difficult for cells inside the graft to obtain nutrients and nutritional support through osmosis. Therefore, early vascularization of the graft plays an important role in the survival of peripheral nerves in the body after transplantation.

[0006] The ultimate goal of peripheral nerve vascularization is to form functional blood vessels around the graft, which requires that the nerve scaffold material has good tissue compatibility with angiogenic cells to facilitate blood vessel ingrowth. Appropriate external and internal structures can support seed cell adhesion, promote seed cell differentiation, growth and axon regeneration, and prevent connective tissue ingrowth. Jiang Liangfu et al. used VEGF nanocapsules to modify decellularized nerve scaffolds to promote tissue engineering nerve prevascularization. In terms of material surface modification, by implanting slow-release growth factors into tissue engineering nerves, angiogenic cells can be induced to migrate and proliferate into the scaffold material, thereby forming a capillary network. However, growth factors such as VEGF have the disadvantages of being easily tumorigenic, unstable biological activity, and expensive.

[0007] Astragalus is the dried root of Astragalus mongolica and Astragalus membranaceus, which belong to the Leguminosae family. It is a traditional tonic Chinese medicine with a long history and wide application. Traditional Chinese medicine believes that Astragalus has the functions of nourishing qi and blood, strengthening the body and eliminating evil, nourishing the heart and promoting blood circulation, and strengthening the spleen and eliminating dampness. The main components of Astragalus are astragalus polysaccharides, astragalus saponins, amino acids, etc. Astragalus polysaccharides are the main active ingredients of Astragalus, which have a wide range of pharmacological activities and mechanisms of action. They can promote the proliferation of vascular endothelial cells and achieve the purpose of promoting angiogenesis. They have broad application prospects in promoting angiogenesis.

[0008] Patent CN 112546303 B relates to a nerve repair material and a preparation method thereof, wherein the nerve repair material comprises an outer tube and an inner core matrix; the outer tube comprises a multilayer round tube formed by curling an animal-derived decellularized matrix material and vacuum pressing; the inner core matrix comprises a natural polymer material and axially oriented microchannels distributed in the natural polymer material. Through the synergistic effect of the outer tube and the inner core matrix, the formation of neuromas on the repaired section can be reduced and the recovery of nerve function can be promoted, but it is only a neural structure and cannot promote nerve vascularization. CN 105169486 B provides a nerve repair material combined with decellularized nerve application, which is composed of decellularized allogeneic or decellularized xenogeneic nerves, repair materials, microtubule protein inhibitors, neurotrophic factors and stem cells, has good biocompatibility, and has the dual effects of preventing neuroma formation and promoting defective nerve repair, but cannot effectively promote the vascularization of allogeneic nerves to provide nutrition and cells required for repair. Summary of the invention

[0009] The purpose of the present invention is to describe a method for preparing an allogeneic nerve repair material for promoting angiogenesis.

[0010] The present invention uses osmotic pressure change combined with ultrasonic treatment of peripheral nerves to prepare decellularized allogeneic nerves, and then compound sodium alginate microcapsules containing astragalus polysaccharides, and further reduce the immunogenicity thereof by irradiation. While removing antigens, no organic solvent is introduced.

[0011] In order to achieve the above purpose, the technical solution adopted by the present invention is: A vascularization-promoting allogeneic nerve repair material and a preparation method thereof, the method being as follows: Step 1, obtain allogeneic peripheral nerves under sterile conditions, wash them with physiological saline and store them below -75°C for later use; Step 2, taking out the deep-frozen allogeneic nerve and thawing it at room temperature, and rinsing it with PBS buffer and ultrasonic vibration for 6 to 12 hours; Step 3, the allogeneic nerve is placed in a hypertonic saline solution and ultrasonically vibrated for 3 to 12 hours, and then ultrasonically rinsed with PBS buffer solution for 3 times, each time for 3 to 5 minutes; Step 4, the allogeneic nerve is placed in purified water and ultrasonically vibrated for 3 to 12 hours, and then ultrasonically rinsed with PBS buffer for 1 to 5 times, each time for 3 to 5 minutes; Step 5, repeat step 3 and step 4 1 to 5 times; Step 6, the allogeneic nerve treated in the previous step is placed in a closed extraction kettle for supercritical carbon dioxide treatment at a temperature of 20-50°C and a pressure of 10-45MPa; the carbon dioxide flow rate is 10-22L / h, and the time is 1-5h; the allogeneic nerve enters the separation kettle, and the temperature is adjusted to 50-60°C. In the separation kettle, the carbon dioxide is converted from a supercritical state to a gaseous state, leaving the decellularized allogeneic nerve for use; Step 7, preparing a 0.5-2.0 mg / L astragalus polysaccharide suspension; using the astragalus polysaccharide suspension as a solvent, adding sodium alginate, and stirring in a water bath at 30-50° C. until the sodium alginate is dissolved to obtain a 1-3% sodium alginate solution; Step 8: Using a high voltage electrostatic field capsule forming device, the mixed solution is heated at a voltage of (2.0-5.0) ×10 4 v. Dropping into 0.1-0.5 mol / L CaCl2 solution at a propulsion speed of 30-80 mm / L to form astragalus polysaccharide-calcium alginate gel microcapsules; collecting astragalus polysaccharide-calcium alginate gel microcapsules by centrifugation, and freeze-drying to prepare microcapsule powder; Step 9, physically adhering the astragalus polysaccharide-calcium alginate microcapsules to the surface of the allogeneic nerve prepared in step 5, with an adhesion amount of 0.1 to 0.5 mg / cm; Step 10: After packaging the astragalus polysaccharide-calcium alginate microcapsules obtained in step 9, irradiation sterilization is performed at a sterilization dose of 15 to 25 kGy.

[0012] Furthermore, allogeneic nerves are myelinated nerve fibers in human spinal nerves, including but not limited to sciatic nerves, femoral nerves, radial nerves, and the like.

[0013] Furthermore, steps (3) and (4) specifically include: the ultrasonic frequency during ultrasonic oscillation rinsing is 10 to 30 kHz.

[0014] Furthermore, the pH value of the PBS buffer in the step is 7.1-7.4.

[0015] Furthermore, the sterilization dose in step 10 is 15 to 25 kGy.

[0016] Furthermore, in the step, the particle size of the astragalus polysaccharide-calcium alginate microcapsules is 10 to 50 um.

[0017] The beneficial effects of the present invention are as follows: (1) The preparation process described in the present invention is carried out by physical methods such as freeze-thaw, osmotic pressure change, supercritical elution, and ultrasound, without introducing organic solvents, thereby significantly improving the biocompatibility of allogeneic nerves; (2) Astragalus polysaccharide is used to replace vascular growth factor to promote angiogenesis, which is non-tumorigenic and low-cost; (3) Astragalus polysaccharide uses sodium alginate, which has good biocompatibility and is easily degradable, and has good biocompatibility and is not likely to affect nerve repair. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Electron microscopy of vascularized allogeneic nerve repair material, surface composited with astragalus polysaccharide sustained-release microcapsules, particle size of 10-50um; Figure 2 Electron microscopy of acellular allogeneic nerve repair materials without astragalus polysaccharide complex showed no cell attachment; Figure 3 Astragalus polysaccharide sustained-release microcapsules; Figure 4 Astragalus polysaccharide sustained-release microcapsules Allogeneic nerve repair material Astragalus polysaccharide sustained-release curve; Figure 5 Observation of HE blood vessel formation in in vivo repair experiment of vascularized allogeneic nerve repair materials. Implementation

[0019] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved clearer, the technical solutions of the embodiments of the present invention are further described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] The present invention will be further described below in conjunction with specific embodiments. Example 1

[0021] A vascularization-promoting allogeneic sciatic nerve repair material and a preparation method thereof are carried out according to the following steps: (1) Obtain human sciatic nerve under sterile conditions, wash with saline, and store below -75°C for later use; (2) The deep-frozen sciatic nerve was removed and thawed at room temperature, and then ultrasonically rinsed with PBS buffer (pH = 7.1) for 6 h at an ultrasonic frequency of 10 kHz; (3) The sciatic nerve was placed in a hypertonic saline solution and ultrasonically vibrated for 3 hours, and then ultrasonically rinsed with PBS buffer (pH = 7.1) for 3 times at an ultrasonic frequency of 10 kHz, for 3 minutes each time; (4) The sciatic nerve was placed in purified water and ultrasonically vibrated for 3 h, and then ultrasonically rinsed with PBS buffer three times at an ultrasonic frequency of 10 kHz, for 3 min each time; (5) Repeat steps 3 and 4 three times to obtain the sciatic nerve; (6) The sciatic nerve treated in the previous step is placed in a closed extraction kettle for supercritical carbon dioxide treatment at a temperature of 20°C and a pressure of 10 MPa; the carbon dioxide flow rate is 10 L / h and the time is 1 hour; the sciatic nerve enters the separation kettle and the temperature is adjusted to 50°C. In the separation kettle, the carbon dioxide is converted from a supercritical state to a gaseous state, leaving the decellularized sciatic nerve for use; (7) Prepare a 0.5 mg / L astragalus polysaccharide suspension; use the astragalus polysaccharide suspension as a solvent, add sodium alginate, and stir in a 30°C water bath until the sodium alginate is dissolved to obtain a 1% sodium alginate solution; (8) Using a high-voltage electrostatic field capsule forming device, the mixed solution was heated at a voltage of 2.0×10 4 v. The mixture was dripped into a 0.1 mol / L CaCl2 solution at a propulsion speed of 30 mm / L to form astragalus polysaccharide-calcium alginate gel microcapsules; the astragalus polysaccharide-calcium alginate gel microcapsules were collected by centrifugation and freeze-dried to prepare microcapsule powder; (9) The astragalus polysaccharide-calcium alginate microcapsules were physically adhered to the surface of the sciatic nerve prepared in (5) at an adhesion amount of 0.1 mg / cm; (10) The composite astragalus polysaccharide-calcium alginate microcapsules of sciatic nerve obtained in (9) are packaged and then sterilized by irradiation at a sterilization dose of 15 kGy. Example 2

[0022] A vascularization-promoting allogeneic sciatic nerve repair material and a preparation method thereof are carried out according to the following steps: (1) Obtain the human radial nerve under sterile conditions, wash it with saline, and store it below -75°C for later use; (2) Remove deep-frozen allogeneic nerves and thaw at room temperature, then rinse with ultrasonic vibration in PBS buffer (pH = 7.3) for 6 to 12 hours at an ultrasonic frequency of 20 kHz; (3) The radial nerve was placed in hypertonic saline and ultrasonically vibrated for 6 hours, and then ultrasonically rinsed with PBS buffer (pH = 7.3) for 3 times at an ultrasonic frequency of 20 kHz, for 5 minutes each time; (4) Place the radial nerve in purified water and ultrasonically vibrate for 5 h, then rinse it with PBS buffer (pH = 7.3) ultrasonically vibrate twice, each time for 5 min; (5) Repeat steps 3 and 4 three times; (6) The radial nerve treated in the previous step is placed in a closed extraction kettle for supercritical carbon dioxide treatment at a temperature of 30°C and a pressure of 30 MPa; the carbon dioxide flow rate is 15 L / h and the time is 3 hours; the radial nerve enters the separation kettle and the temperature is adjusted to 55°C. In the separation kettle, the carbon dioxide is converted from a supercritical state to a gaseous state, leaving the decellularized radial nerve for use; (7) Prepare a 1 mg / L astragalus polysaccharide suspension; use the astragalus polysaccharide suspension as a solvent, add sodium alginate, and stir in a 37°C water bath until the sodium alginate is dissolved to obtain a 2% sodium alginate solution; (8) Using a high-voltage electrostatic field capsule forming device, the mixed solution was heated at a voltage of 3.0×10 4 v. The mixture was dripped into a 0.2 mol / L CaCl2 solution at a propulsion speed of 50 mm / L to form astragalus polysaccharide-calcium alginate gel microcapsules; the astragalus polysaccharide-calcium alginate gel microcapsules were collected by centrifugation and freeze-dried to prepare microcapsule powder; (9) Physically adhere the astragalus polysaccharide-calcium alginate microcapsules to the surface of the radial nerve in (6) with an adhesion amount of 0.2 mg / cm; (10) The radial nerve composite astragalus polysaccharide-calcium alginate microcapsules obtained in (9) are packaged and sterilized by irradiation at a sterilization dose of 20 kGy. Example 3

[0023] A vascularization-promoting allogeneic sciatic nerve repair material and a preparation method thereof are carried out according to the following steps: (1) Obtain human femoral nerve under sterile conditions, wash with saline, and store below -75°C for later use; (2) The deep-frozen femoral nerve was removed and thawed at room temperature, and then ultrasonically rinsed with PBS buffer (pH = 7.1) for 6 h at an ultrasonic frequency of 15 kHz; (3) The femoral nerve was placed in a hypertonic saline solution and ultrasonically vibrated for 3 hours, and then ultrasonically rinsed with PBS buffer (pH = 7.1) for 3 times, with an ultrasonic frequency of 15 kHz and each time for 4 minutes; (4) Place the femoral nerve in purified water and ultrasonically vibrate for 3 hours, then rinse it with PBS buffer ultrasonically for 3 times at a frequency of 10 kHz, for 3 minutes each time; (5) Repeat steps 3 and 4 three times; (6) The femoral nerve treated in the previous step is placed in a closed extraction kettle for supercritical carbon dioxide treatment at a temperature of 20°C and a pressure of 10 MPa; the carbon dioxide flow rate is 10 L / h and the time is 1 hour; the sciatic nerve enters the separation kettle and the temperature is adjusted to 50°C. In the separation kettle, the carbon dioxide is converted from a supercritical state to a gaseous state, leaving the decellularized femoral nerve for use; (7) Prepare a 0.5 mg / L astragalus polysaccharide suspension; use the astragalus polysaccharide suspension as a solvent, add sodium alginate, and stir in a 37°C water bath until the sodium alginate is dissolved to obtain a 1.5% sodium alginate solution; (8) Using a high-voltage electrostatic field capsule forming device, the mixed solution was heated at a voltage of 2.0×10 4 v. The mixture was dripped into a 0.1 mol / L CaCl2 solution at a propulsion speed of 30 mm / L to form astragalus polysaccharide-calcium alginate gel microcapsules; the astragalus polysaccharide-calcium alginate gel microcapsules were collected by centrifugation and freeze-dried to prepare microcapsule powder; (9) Physically adhering the astragalus polysaccharide-calcium alginate microcapsules to the surface of the femoral nerve prepared in (5) with an adhesion amount of 0.1 mg / cm; (10) The composite astragalus polysaccharide-calcium alginate microcapsules of the femoral nerve obtained in (9) are packaged and then irradiated for sterilization at a sterilization dose of 25 kGy.

[0024] Comparative Example 1 The experimental group in this comparative example is an allogeneic sciatic nerve repair material of composite astragalus polysaccharide-sodium alginate microcapsules; the control group is an allogeneic sciatic nerve repair material obtained by directly applying an astragalus polysaccharide suspension and then freeze-drying it, and its preparation method is the same as that described in Example 2.

[0025] Experimental group: 1.0 mg / L astragalus polysaccharide suspension was prepared, and sodium alginate was added to the astragalus polysaccharide suspension as solvent. The mixture was stirred in a 37°C water bath until the sodium alginate was dissolved to obtain a 2% sodium alginate solution. The mixed solution was stirred at a voltage of 3.0×10 4 v. The microcapsules were dripped into 0.2 mol / L CaCl2 solution at a speed of 50 mm / L to form astragalus polysaccharide-calcium alginate gel microcapsules, which were physically adsorbed on the surface of allogeneic nerves after freeze-drying.

[0026] Control group: 1.0 mg / L astragalus polysaccharide suspension was prepared and directly attached to the surface of allogeneic nerves.

[0027] Take 2cm of the experimental group and the control group respectively and put them into centrifuge tubes, add 5mL phosphate buffer, and place them in an oscillator at room temperature at 120 r / min. Take the cleaning solution every hour to detect the concentration of astragalus polysaccharide in the cleaning solution. The detection method uses glucose as the standard and then ethanol precipitation and then phenol-sulfuric acid colorimetric determination, and then add fresh PBS to continue observation, draw concentration curves, and analyze drug release. The results showed that the astragalus polysaccharide in the control group that was not compounded with sodium alginate microcapsules was completely released within 5 hours, and the astragalus polysaccharide in the experimental group that was compounded with sodium alginate microcapsules was still released after 16 hours.

[0028] Comparative Example 2 In this comparative example, the control group is an allogeneic sciatic nerve repair material without astragalus polysaccharide, and its preparation method is the same as that described in Example 1; the experimental group is an allogeneic sciatic nerve repair material compounded with astragalus polysaccharide-sodium alginate microcapsules, and its preparation method is the same as that described in Example 1.

[0029] The experimental group and the control group were used in the rabbit hind leg sciatic nerve transplantation repair experiment to observe the repair effect. Ten healthy rabbits weighing about 2.5 kg were selected, regardless of gender. They were anesthetized with 3% sodium pentobarbital at a ratio of 1 ml / kg. After shaving the hair on the proximal and lateral sides of the lower limbs, the iodine was disinfected. After the skin and mucosa were cut layer by layer with a scalpel, the muscles were bluntly separated and the sciatic nerve was freed. A defect of about 1 cm in length was artificially created, and the experimental group and control group materials were implanted for transplantation repair. After suturing, the wound was rinsed with gentamicin. The experimental group was implanted on the left leg side, and the control group was implanted on the right leg side. The samples were collected 4 weeks after surgery, and the animals were killed by excessive anesthesia. The layers were cut, the muscles were bluntly separated, and the transplanted nerves were cut and fixed in 4% formaldehyde solution for 72 hours. The fixed tissue blocks were dehydrated with conventional ethanol series, paraffin-embedded and tissue sections were prepared, and the repair effect and vascularization of the transplanted area were observed after HE staining. Results 4 weeks after surgery, a large number of new blood vessels were observed in the epineurium of the experimental group (compound group), and they grew into the nerve; only a small amount of new blood vessels were observed in the epineurium of the control group (uncompounded group).

[0030] Different from the prior art, the present invention provides a vascularization-promoting allogeneic sciatic nerve repair material prepared by the aforementioned method and its preparation method, which can effectively improve the biocompatibility of allogeneic nerves, promote vascularization, and promote the peripheral nerve repair effect while reducing allogeneic nerve antigens.

[0031] Those skilled in the art should understand that the materials and methods described in the present invention are not limited to the embodiments described in the specific embodiments, and the above specific description is only for the purpose of explaining the present invention, and is not used to limit the present invention. Those skilled in the art derive other embodiments based on the technical solution of the present invention, which also belong to the technical innovation scope of the present invention, and the protection scope of the present invention is defined by the claims and their equivalents.

Claims

1. A vascularization-promoting allogeneic nerve repair material and a preparation method thereof, characterized in that: Astragalus polysaccharide sustained-release microcapsules were compounded on the surface of acellular allogeneic nerves.

2. The vascularization-promoting allogeneic nerve repair material and the preparation method thereof according to claim 1, characterized in that: The following steps are involved: Step 1, obtain allogeneic peripheral nerves under sterile conditions, wash them with physiological saline and store them below -75°C for later use; Step 2, taking out the deep-frozen allogeneic nerve and thawing it at room temperature, and rinsing it with PBS buffer and ultrasonic vibration for 6 to 12 hours; Step 3, the allogeneic nerve is placed in a hypertonic saline solution and ultrasonically vibrated for 3 to 12 hours, and then ultrasonically rinsed with PBS buffer solution for 3 times, each time for 3 to 5 minutes; Step 4, the allogeneic nerve is placed in purified water and ultrasonically vibrated for 3 to 12 hours, and then ultrasonically rinsed with PBS buffer for 1 to 5 times, each time for 3 to 5 minutes; Step 5, repeat step 3 and step 4 1 to 5 times; Step 6, the allogeneic nerve treated in the previous step is placed in a closed extraction kettle for supercritical carbon dioxide treatment at a temperature of 20-50°C and a pressure of 10-45MPa; the carbon dioxide flow rate is 10-22L / h, and the time is 1-5h; the allogeneic nerve enters the separation kettle, and the temperature is adjusted to 50-60°C. In the separation kettle, the carbon dioxide is converted from a supercritical state to a gaseous state, leaving the decellularized allogeneic nerve for use; Step 7, preparing a 0.5-2.0 mg / L astragalus polysaccharide suspension; using the astragalus polysaccharide suspension as a solvent, adding sodium alginate, stirring in a water bath at 30-50° C. until the sodium alginate is dissolved, and preparing a sodium alginate solution with a concentration of 1-3%; Step 8: Using a high voltage electrostatic field capsule forming device, the mixed solution is heated at a voltage of (2.0-5.0) ×10 4 v. Dropping into 0.1-0.5 mol / L CaCl2 solution at a propulsion speed of 30-80 mm / L to form astragalus polysaccharide-calcium alginate gel microcapsules; collecting astragalus polysaccharide-calcium alginate gel microcapsules by centrifugation, and freeze-drying to prepare microcapsule powder; Step 9, physically adhering the astragalus polysaccharide-calcium alginate microcapsules to the surface of the allogeneic nerve prepared in step 5, with an adhesion amount of 0.1 to 0.5 mg / cm; Step 10: After packaging the astragalus polysaccharide-calcium alginate microcapsules obtained in step 9, irradiation sterilization is performed at a sterilization dose of 15 to 25 kGy.

3. The vascularization-promoting allogeneic nerve repair material and the preparation method thereof according to claim 1, characterized in that: The allogeneic nerves are myelinated nerve fibers in human spinal nerves, including but not limited to the sciatic nerve, femoral nerve, radial nerve, etc.

4. The vascularization promoting allogeneic nerve repair material and the preparation method thereof according to claim 2, characterized in that: The steps (3) and (4) specifically include: the ultrasonic frequency during ultrasonic oscillation rinsing is 10 to 30 kHz.

5. The vascularization promoting allogeneic nerve repair material and the preparation method thereof according to claim 2, characterized in that: The pH value of the PBS buffer in the step is 7.1-7.

4.

6. The vascularization promoting allogeneic nerve repair material and the preparation method thereof according to claim 2, characterized in that: The sterilization dose in step 10 is 15 to 25 kGy.

7. The vascularization promoting allogeneic nerve repair material and the preparation method thereof according to claim 2, characterized in that: In the step, the particle size of the astragalus polysaccharide-calcium alginate microcapsule is 10 to 50 μm.

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