Brain taking method of experimental animal

Abstract

The invention relates to a brain taking method for an experimental animal, which comprises the following steps: S1, cutting the skin of the skull crest along a skin cutting line of the skull crest of the killed experimental animal so as to expose the skeleton of the skull crest; s2, the connecting line of the two eyes serves as a nasal bone cutting line, and shearing treatment is conducted along the nasal bone cutting line so that the nasal bone can be broken; s3, one end of the sagittal seam extends to the cervical vertebra cut-off position, the other end of the sagittal seam extends to the nasal bone cut-off position to form a skull cutting line, and cutting-up treatment is conducted along the skull cutting line till the skull is broken; s4, opening the left skull towards the left side along the skull breaking gap, and opening the right skull towards the right side to expose the complete brain tissue; and S5, stripping a nerve connection point between the brain tissue and the skull base, so that the head of the experimental animal is inversely placed, and the brain tissue falls off from the inside of the brain shell under the action of gravity. According to the method, the integrity of the sampled brain tissue can be ensured; the method is short in brain taking time, and the experiment efficiency is improved.

Description

Technical Field

[0001] The present disclosure relates to the field of science and technology, and in particular, to a method for extracting brains from experimental animals. Background Art

[0002] In experimental studies, researchers often remove various tissues and organs from rats or mice, such as liver, heart, spleen, lung, kidney, brain, thymus, knee joint, etc., according to the purpose of the experiment. In particular, rat or mouse brain tissue is an important material in experimental research. Since the weight of brain tissue is more stable than body weight, researchers need to calculate the mass ratio of organs to brain tissue, i.e., the visceral brain index, in order to evaluate the changes in different organs of animals under disease conditions and before and after drug treatment. Brain tissue can provide important information on neurons, neural circuits, neurotransmitters, etc. Therefore, in animal experiments on neurological disease models, it is often necessary to locate and sample brain tissue, such as the hippocampus, substantia nigra, or other neural nucleus tissues. Therefore, it is very important to ensure the integrity of the obtained rat or mouse brain tissue.

[0003] At present, there are several methods for obtaining brain tissue from experimental animals: Method 1: After anesthetizing rats or mice, use scissors to cut off the rat or mouse head, cut the skin on the top of the skull to expose the skull, use tissue scissors and bone-cutting forceps to cut the skull little by little from the foramen magnum to expose the brain tissue, use small scissors to cut the cranial nerves, and remove the brain tissue; Method 2: After anesthetizing rats or mice, use tissue scissors to cut the connection between the skull and the cervical vertebrae, cut the skin on the top of the skull along the sagittal suture, insert the head of the tissue scissors into the foramen magnum and cut the skull towards the left eye socket, cut to the eye socket, perform the same operation on the right side, and then cut the frontal bone between the rat or mouse eye sockets horizontally, hold the hook forceps in the left hand and insert them into the rat or mouse eye socket to fix the skull, hold the curved forceps in the right hand and directly clamp the bone at the foramen magnum, lift the skull from bottom to top to expose the brain tissue, use forceps to push the brain tissue upward from the cerebellum, use small scissors to cut the cranial nerves, and remove the brain tissue. Method 3: The rat or mouse is anesthetized and then killed, and the connection between the skull and the cervical vertebra is cut with tissue scissors, and then the skin on the top of the skull is cut along the sagittal suture, and the fascia on the top of the skull is cleaned. The occipital bone is cut from the foramen magnum of the rat or mouse to the lambdoid point along the sagittal suture using tissue scissors, and the frontal bone is vertically pierced along the extension direction of the sagittal suture at 0.5-0.8 cm from the anterior fontanelle to the frontal bone of the rat or mouse to the base of the skull using curved hemostat. At this time, the clamp body of the curved hemostat enters the skull of the rat or mouse. Since the clamp body has a certain thickness, the parietal bone of the rat or mouse will be directly stretched open and divided into left and right parts along the sagittal suture. The parietal bone is then pried apart using curved hemostat. After the brain tissue of the rat or mouse is completely exposed, the connection between the brain tissue and the nerves at the base of the skull is cut using small scissors; the brain tissue is removed.

[0004] However, the above methods for obtaining brain tissue all have the following disadvantages: (1) It takes a long time. The average time for rats is 10-15 minutes per rat and the average time for mice is 4-6 minutes per mouse. A batch of animal experiments usually involves 100 or more rats or mice. Therefore, when collecting brain tissue samples, multiple experimenters are often required to carry out the work at the same time, wasting laboratory manpower.

[0005] (2) The skull of a rat or mouse is very hard. Using bone forceps or tissue scissors to break the skull to obtain brain tissue is very laborious, which affects the efficiency of the experiment and will inevitably affect or even destroy the integrity of the brain tissue, thereby affecting the subsequent positioning and sampling of the brain tissue.

[0006] (3) The experimenter is required to have a high level of proficiency in operation, which is not conducive to learning for novices. Summary of the invention

[0007] The purpose of the present disclosure is to provide a method for extracting brains from experimental animals, which can effectively prevent the sampled brain tissue from containing other tissues and ensure the integrity of the sampled brain tissue; and the method has a short brain extraction time, thereby improving experimental efficiency.

[0008] In order to achieve the above object, the present disclosure provides a method for removing the brain of an experimental animal, the method comprising the following steps: S1. Cut the skin of the skull of the killed experimental animal along the skin cutting line to expose the skull bones; S2, using the line connecting the two eyes as the nasal bone cutting line, and performing shearing along the nasal bone cutting line to disconnect the nasal bone; S3, extending one end of the sagittal suture to the shearing position of the cervical vertebra, and extending the other end of the sagittal suture to the shearing position of the nasal bone to form a skull cutting line, and performing a cutting process along the skull cutting line until the skull is disconnected; S4. Open the left side of the skull to the left and the right side of the skull to the right along the fractured gap of the skull to expose the complete brain tissue; S5. The nerve connection points between the brain tissue and the skull base are peeled off, and the head of the experimental animal is placed upside down. The brain tissue falls off from the inside of the skull under the action of gravity, and the complete brain tissue of the experimental animal is obtained.

[0009] Optionally, in step S1, the skin cutting line is formed by connecting the midpoints of the line connecting the two eyes and the midpoints of the line connecting the two ears of the experimental animal and extending to the place where the cervical skin is cut.

[0010] Optionally, step S3 also includes: making the inner edge of the blade on one side of the scissors abut against the first end point of the skull cutting line, making the inner edge of the blade on the other side of the scissors abut against the second end point of the skull cutting line, and cutting along the skull cutting line until the skull is broken.

[0011] Optionally, the number of cutting times in the cutting process is 2-3 times.

[0012] Optionally, step S4 also includes: inserting the tips of the blades on both sides of the scissors into the middle position of the skull fracture gap, and then opening the scissors to flip the left side of the skull to the left, and flip the right side of the skull to the right, so as to expose the complete brain tissue.

[0013] Optionally, the tips of the scissors on both sides are inserted into the middle of the skull fracture gap to a depth of 1-2 mm.

[0014] Optionally, in step S1, the method further includes: The experimental animal was anesthetized, and then the fur at the cervical vertebrae of the experimental animal was cut, and the cervical spinal cord of the experimental animal was cut.

[0015] Optionally, the method further comprises: after the experimental animal is anesthetized, blood is collected from the abdominal aorta or the eyeball of the experimental animal.

[0016] Optionally, the experimental animal is selected from rodent experimental animals; Preferably, the experimental rodent is selected from experimental rats and / or experimental mice.

[0017] Optionally, the removed intact brain tissue is stored and fixed in paraformaldehyde solution.

[0018] Through the above technical scheme, the present disclosure provides a method for extracting the brain of an experimental animal, which can effectively avoid the sampled brain tissue from containing other tissues and ensure the integrity of the sampled brain tissue; and the method has a short brain extraction time, improves the experimental efficiency, effectively reduces the number of experimental personnel required, and saves the time of the experimental personnel.

[0019] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings: Figure 1 The following are the detailed steps for removing brains from experimental rats and mice disclosed in the present invention.

[0021] Figure 2 It refers to the integrity of brain tissues obtained from experimental rats and mice using different methods at the same sampling time.

[0022] Figure 3It is the sampling time of experimental rats and experimental mice with the same brain tissue integrity, the brain tissue integrity at the same sampling time, and the brain tissue to body weight ratio at the same sampling time.

[0023] Figure 4 A top view of a mouse skull.

[0024] Figure 5 It is a top view of the mouse head and its positional relationship with the brain tissue.

[0025] Figure 6 A top view of the mouse's head and the skin incision line.

[0026] Figure 7 This is a top view of a mouse lying prone and the location where the cervical vertebrae were cut.

[0027] Description of Reference Numerals 1 Skin cutting line; 2 Nasal bone cutting line; 3 Skull cutting line; 4 Cervical vertebra cutting line. DETAILED DESCRIPTION

[0028] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0029] like Figure 1 and 4 -7, the present disclosure provides a method for extracting brains from experimental animals, the method comprising the following steps: S1, cutting the skin of the skull of the killed experimental animal along the skin cutting line 1 to expose the skull bones; S2, taking the line connecting the two eyes as the nasal bone cutting line 2, and performing shearing along the nasal bone cutting line 2 to disconnect the nasal bone; S3, extending one end of the sagittal suture to the cervical vertebra shearing position 4, and extending the other end of the sagittal suture to the nasal bone shearing position to form a skull cutting line 3, and performing a scoring process along the skull cutting line 3 until the skull is disconnected; S4. Open the left side of the skull to the left and the right side of the skull to the right along the fractured gap of the skull to expose the complete brain tissue; S5. The nerve connection points between the brain tissue and the skull base are peeled off, and the head of the experimental animal is placed upside down. The brain tissue falls off from the inside of the skull under the action of gravity, and the complete brain tissue of the experimental animal is obtained.

[0030] In the present disclosure, the method can effectively avoid the sampled brain tissue from containing other tissues and ensure the integrity of the sampled brain tissue; and the method can greatly shorten the time required for rat and mouse brain extraction experiments and save the physical strength of the experimenters; the average time for rat brain tissue extraction in the present disclosure is 4 minutes per rat, and the average time for mouse brain tissue extraction is 2 minutes per rat, which greatly improves the speed of brain tissue extraction, effectively reduces the number of experimenters required, saves the experimenters' time, and improves the experimental efficiency.

[0031] In step S2 of the present disclosure, "the line connecting both eyes" refers to the line connecting the inner corners of both eyes and the position near it, which can be the line connecting the inner corners of both eyes, or a line near and parallel to the line connecting the inner corners of both eyes, which can be used as the nasal bone cutting line. The shearing process is performed along the nasal bone cutting line, and this step can make the subsequent step of opening the skull more labor-saving.

[0032] In one embodiment of the present disclosure, in step S1, the skin cutting line 1 is formed by connecting the midpoints of the line connecting the two eyes and the midpoints of the line connecting the two ears of the experimental animal and extending to the place where the cervical skin is cut.

[0033] In one embodiment of the present disclosure, step S3 also includes: making the inner edge of the blade on one side of the scissors against the first end point of the skull cutting line 3, making the inner edge of the blade on the other side of the scissors against the second end point of the skull cutting line 3, and performing a cutting process along the skull cutting line 3 until the skull is disconnected. In the above embodiment, the skull cutting line coincides with the sagittal suture and is an extension of the sagittal suture. One end of the sagittal suture extends to the cervical vertebra shearing point, and the connection point can be used as the first end point or the second end point of the skull cutting line; the other end of the sagittal suture extends to the nasal bone shearing point, and the connection point can be used as the second end point or the first end point of the skull cutting line. When performing the cutting process, it should be noted that the tip of the knife should not be on the same horizontal line as the brain tissue, and should be higher than the horizontal space where the brain tissue is located to avoid the tip of the knife being inserted too deeply to damage the brain tissue and affect the integrity of the sample; preferably, the number of cutting times of the cutting process is 2-3 times. In the present disclosure, "skull" refers to the frontal bone, parietal bone, interparietal bone and occipital bone, that is, the skull cutting line passes through the frontal bone, parietal bone, interparietal bone and occipital bone, and coincides with the sagittal suture formed by the left parietal bone and the right parietal bone.

[0034] In one embodiment of the present disclosure, step S4 further includes: inserting the tips of the blades on both sides of the scissors into the middle position of the skull fracture gap, and then opening the scissors to open the left skull to the left and the right skull to the right to expose the complete brain tissue. Preferably, the insertion depth of the tips of the blades on both sides of the scissors into the middle position of the skull fracture gap is 1-2 mm.

[0035] In the present disclosure, "left side" refers to the side where the left side of the mouse body or the left eye is located, and "right side" refers to the side where the right side of the mouse body or the right eye is located.

[0036] In step S5 of the present disclosure, placing the head of the experimental animal upside down means that the side with the intact brain tissue exposed faces downward. The neural connection point between the brain tissue and the skull base refers to the tiny channel between the skull bone marrow and the meninges, which is a snow-white connection point visible to the naked eye.

[0037] In the present disclosure, scissors may be used to perform the shearing process and the scoring process, and the scissors may be pointed surgical scissors and / or ordinary scissors.

[0038] In one embodiment of the present disclosure, in step S1, the method further includes: The experimental animal was anesthetized, and then the fur at the cervical vertebrae of the experimental animal was cut, and the cervical spinal cord of the experimental animal was cut.

[0039] In the above embodiment, if Figure 7 As shown, the cervical fur and cervical spinal cord of the experimental animal are cut in a direction parallel to the line connecting the two eyes; this step can kill the experimental animal and form a cervical cutting point 4 and a cervical skin cutting point at the cervical part.

[0040] According to the present disclosure, the method further comprises: after the experimental animal is anesthetized, blood is collected from the abdominal aorta or the eyeball of the experimental animal. Collecting all the blood can avoid endogenous interference of blood in the cerebral blood vessels on subsequent detection of brain tissue pathology and biochemical indicators.

[0041] According to the present disclosure, the experimental animal is selected from rodent experimental animals. Preferably, the rodent experimental animal is selected from experimental rats and / or experimental mice.

[0042] In one embodiment of the present disclosure, the removed intact brain tissue is stored in a paraformaldehyde solution for fixation, wherein the mass concentration of paraformaldehyde in the paraformaldehyde solution is 4%.

[0043] The present disclosure is further described in detail below through examples.

[0044] Experimental rats: 28 SPF SD male rats, 8 weeks old, 160-200 g, purchased from Beijing Weitonglihua Experimental Animal Co., Ltd.

[0045] Experimental mice: 32 SPF-grade db / db male mice, 8 weeks old, 20-25 g; purchased from Jiangsu Saiye Biological Experimental Animal Co., Ltd.

[0046] This experiment was approved by the Experimental Animal Welfare Ethics Committee of the Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences. The ethical numbers of rat and mouse animal experiments are 2024B085 and 2024B133, respectively. Rats and mice were uniformly fed in the Experimental Animal Center of the Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences. The animal room was clean and bright, with good ventilation, and the temperature was 18~22℃ and the humidity was 45%~55%.

[0047] Example 1 S1. Anesthetize the rats, draw blood from the abdominal aorta and remove the eyeballs of the rats, cut the fur at the cervical vertebrae of the rats in a direction perpendicular to the cervical vertebrae of the rats, and cut the connection between the skull and the cervical vertebrae of the rats; After the rats were killed, the midpoints of the line connecting the two eyes and the two ears of the rats were connected and extended to the place where the skin of the cervical spine was cut to form a skin cutting line 1. The skin of the rat's skull was cut along the skin cutting line 1 with scissors to expose the bones of the skull; S2, taking the line connecting the two eyes as the nasal bone cutting line 2, and performing shearing along the nasal bone cutting line 2 to disconnect the nasal bone; S3, extending one end of the sagittal suture to the cervical vertebrae shearing point 4, and extending the other end of the sagittal suture to the nasal bone shearing point to form a skull cutting line 3, making the inner edge of the blade on one side of the scissors against the first end point of the skull cutting line 3, making the inner edge of the blade on the other side of the scissors against the second end point of the skull cutting line 3, and cutting along the skull cutting line 3 2-3 times until the skull is disconnected; S4. Insert the tips of the scissors into the middle of the skull fracture (insertion depth is 1 mm), then open the scissors to flip the left side of the skull to the left and the right side of the skull to the right, so that the complete brain tissue is exposed. S5. The nerve connection points between the brain tissue and the skull base are peeled off, and the rat's head is placed upside down so that the brain tissue falls off from the inside of the skull under the action of gravity; thus, the complete brain tissue of the rat is obtained.

[0048] Example 2 S1. Anesthetize the mouse, draw blood from the abdominal aorta and remove the eyeball of the mouse, then cut the fur at the cervical vertebra of the mouse in a direction perpendicular to the cervical vertebra of the mouse, and cut the connection between the skull and the cervical vertebra of the mouse; After killing the mouse, the midpoints of the line connecting the two eyes and the two ears of the mouse were connected and extended to the place where the cervical skin was cut to form skin cutting line 1. The skin of the mouse's skull was cut along the skin cutting line 1 with scissors to expose the skull bones; S2, taking the line connecting the two eyes as the nasal bone cutting line 2, and performing shearing along the nasal bone cutting line 2 to disconnect the nasal bone; S3, extending one end of the sagittal suture to the cervical vertebrae shearing point 4, and extending the other end of the sagittal suture to the nasal bone shearing point to form a skull cutting line 3, making the inner edge of the blade on one side of the scissors against the first end point of the skull cutting line 3, making the inner edge of the blade on the other side of the scissors against the second end point of the skull cutting line 3, and cutting along the skull cutting line 3 2-3 times until the skull is disconnected; S4. Insert the tips of the scissors into the middle of the skull fracture (insertion depth is 1 mm), then open the scissors to flip the left side of the skull to the left and the right side of the skull to the right, so that the complete brain tissue is exposed. S5. The nerve connection points between the brain tissue and the skull base are peeled off, and the mouse's head is placed upside down to allow the brain tissue to fall off from the inside of the skull under the action of gravity; thus, the complete brain tissue of the mouse is obtained.

[0049] Comparative Example 1 After the rat is anesthetized, use scissors to cut off the rat's head, cut the skin on the top of the skull in a direction perpendicular to the line connecting the two eyes to expose the skull, use tissue scissors and bone rongeurs to cut the skull little by little from the foramen magnum toward the frontal bone to expose the brain tissue, use small scissors to cut the cranial nerves and remove the brain tissue.

[0050] Comparative Example 2 After the mouse is anesthetized, use scissors to cut off the rat's skull, cut the skin on the top of the skull perpendicular to the line connecting the two eyes to expose the skull, use tissue scissors and bone rongeurs to cut the skull little by little from the foramen magnum toward the frontal bone to expose the brain tissue, use small scissors to cut the cranial nerves and remove the brain tissue.

[0051] Comparative Example 3 After the rats were anesthetized, tissue scissors were used to cut the connection between the skull and the cervical vertebrae, and the skin on the top of the skull was cut along the sagittal suture. The head of the tissue scissors was inserted into the foramen magnum and the skull was cut toward the left orbit. The skull was cut to the orbit, and the same operation was performed on the right side. The frontal bone between the rat's orbits was cut horizontally. The hook forceps held in the left hand were inserted into the rat's orbit to fix the skull. The curved forceps held in the right hand directly clamped the bone at the foramen magnum, and the skull was opened from bottom to top to expose the brain tissue. The brain tissue was pushed upward from the cerebellum using forceps, and the cranial nerves were cut with small scissors to remove the brain tissue.

[0052] Comparative Example 4 After the mouse is anesthetized, use tissue scissors to cut the connection between the skull and cervical vertebrae, cut the skin on the top of the skull along the sagittal suture, insert the head of the tissue scissors into the foramen magnum and cut the skull towards the left orbit, cut to the orbit, perform the same operation on the right side, and then cut the frontal bone between the mouse orbits horizontally. Hold the hook forceps in the left hand and insert them into the mouse's orbit to fix the skull. Hold the curved forceps in the right hand and directly clamp the bone at the foramen magnum, lift the skull from bottom to top to expose the brain tissue, use forceps to push the brain tissue upward from the cerebellum, use small scissors to cut the cranial nerves, and remove the brain tissue.

[0053] Comparative Example 5 The rats were anesthetized and killed, and the connection between the skull and the cervical vertebrae was cut with tissue scissors, and then the skin on the top of the skull was cut along the sagittal suture, the fascia on the top of the skull was cleaned, and the occipital bone was cut from the rat's foramen magnum to the lambdoid point along the sagittal suture using tissue scissors, and the frontal bone was vertically pierced to the skull base at 0.8 cm from the rat's anterior bregma to the frontal bone in the extended direction of the sagittal suture using curved hemostatic forceps. At this time, the clamp body of the curved hemostatic forceps entered the inside of the rat's skull. Since the clamp body had a certain thickness, the rat's parietal bone would be directly stretched open and divided into left and right parts along the sagittal suture. The parietal bone was then pried apart using curved hemostatic forceps. After the rat's brain tissue was completely exposed, the connection between the brain tissue and the nerves at the skull base was cut using small scissors; the brain tissue was removed.

[0054] Comparative Example 6 The mice were anesthetized and killed, and the connection between the skull and the cervical vertebrae was cut with tissue scissors, and then the skin on the top of the skull was cut along the sagittal suture, the fascia on the top of the skull was cleaned, and the occipital bone was cut from the foramen magnum of the mouse to the lambdoid point along the sagittal suture with tissue scissors, and the frontal bone was vertically pierced to the base of the skull at 0.6 cm from the anterior fontanelle to the frontal bone of the mouse along the extension direction of the sagittal suture with curved hemostat. At this time, the clamp body of the curved hemostat entered the inside of the mouse's skull. Since the clamp body had a certain thickness, the parietal bone of the mouse would be directly stretched open and divided into left and right parts along the sagittal suture. The parietal bone was then pried apart with curved hemostat. After the mouse's brain tissue was completely exposed, small scissors were used to cut the connection between the brain tissue and the nerves at the base of the skull; the brain tissue was removed.

[0055] The “collection time at the same brain tissue integrity”, “brain tissue integrity at the same collection time” and “brain tissue to body weight ratio at the same collection time” of Examples 1-2 and Comparative Examples 1-6 were statistically analyzed. The integrity of the brain tissues collected and the above data are shown in FIG. Figure 2 and 3 As shown, the method disclosed in the present invention requires a short sampling time at the same brain tissue integrity, has a high brain tissue integrity score at the same sampling time, and has a high brain tissue to body weight ratio, and the difference is significant, and the results are statistically significant.

[0056] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0057] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0058] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for removing brains from experimental animals, characterized in that: The method comprises the following steps: S1. Cut the skin on the skull of the killed experimental animal along the skin cutting line (1) to expose the skull bones; S2, using the line connecting the two eyes as the nasal bone cutting line (2), and performing shearing along the nasal bone cutting line (2) to break the nasal bone; S3, extending one end of the sagittal suture to the cervical vertebrae shearing position (4), and extending the other end of the sagittal suture to the nasal bone shearing position to form a skull cutting line (3), and performing a cutting process along the skull cutting line (3) until the skull is disconnected; S4. Open the left side of the skull to the left and the right side of the skull to the right along the fractured gap of the skull to expose the complete brain tissue; S5. The nerve connection points between the brain tissue and the skull base are peeled off, and the head of the experimental animal is placed upside down. The brain tissue falls off from the inside of the skull under the action of gravity, and the complete brain tissue of the experimental animal is obtained.

2. The method according to claim 1, wherein: In step S1, the skin cutting line (1) is formed by connecting the midpoints of the line connecting the two eyes and the two ears of the experimental animal and extending to the place where the cervical skin is cut.

3. The method according to claim 1, wherein: Step S3 also includes: making the inner edge of the blade on one side of the scissors abut against the first end point of the skull cutting line (3), making the inner edge of the blade on the other side of the scissors abut against the second end point of the skull cutting line (3), and performing a cutting process along the skull cutting line (3) until the skull is severed.

4. The method according to claim 3, wherein: The number of times of cutting in the cutting process is 2-3 times.

5. The method according to claim 1, wherein: Step S4 also includes: inserting the tips of the blades on both sides of the scissors into the middle position of the skull fracture gap, and then opening the scissors to open the left side of the skull to the left and the right side of the skull to the right to expose the complete brain tissue.

6. The method according to claim 5, wherein: Insert the tips of the scissors on both sides into the middle of the skull fracture gap to a depth of 1-2 mm.

7. The method according to claim 1, wherein: In step S1, the method further includes: The experimental animal was anesthetized, and then the fur at the cervical vertebrae of the experimental animal was cut, and the cervical spinal cord of the experimental animal was cut.

8. The method according to claim 7, wherein: The method further comprises: after the experimental animal is anesthetized, blood is collected from the abdominal aorta or the eyeball of the experimental animal.

9. The method according to any one of claims 1 to 7, wherein: The experimental animals are selected from rodent experimental animals; Preferably, the experimental rodent is selected from experimental rats and / or experimental mice.

10. The method according to claim 1, wherein: The removed intact brain tissue was stored and fixed in paraformaldehyde solution.

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