Method for removing the brain of an experimental animal

Abstract

The disclosure relates to a brain taking method of experimental animals, which comprises the following steps: S1, cutting the skin of the skull top of the experimental animals that have been killed along the skin cutting line of the skull top to expose the bone of the skull top; S2, taking the line connecting the two eyes as a nasal bone cutting line, and performing cutting treatment along the nasal bone cutting line to separate the nasal bone; S3, extending one end of the sagittal suture to the cervical vertebra cutting position, extending the other end of the sagittal suture to the nasal bone cutting position to form a skull cutting line, and performing cutting treatment along the skull cutting line until the skull is separated; S4, opening the left skull to the left and the right skull to the right along the skull separation gap to expose the complete brain tissue; and S5, peeling the nerve connection point of the brain tissue and the skull base, inverting the head of the experimental animals, and making the brain tissue fall off from the inside of the skull under the action of gravity. The method can guarantee the integrity of the sampled brain tissue, and the brain taking time is short, and the experimental efficiency is improved.

Description

Technical Field

[0001] This disclosure relates to the field of science and technology, and more specifically, to a method for extracting the brain from laboratory animals. Background Technology

[0002] In experimental research, researchers often selectively extract various tissues and organs from rats or mice, such as the liver, heart, spleen, lungs, kidneys, brain, thymus, and knee joints, depending on the experimental objective. Rat or mouse brain tissue, in particular, is a crucial material in experimental research. Because brain tissue weight is more stable than body weight, researchers need to calculate the organ-to-brain mass ratio, or the visceral-brain index, to assess changes in different organs before and after drug treatment in animals under disease conditions. Brain tissue provides important information on neurons, neural circuits, and neurotransmitters; therefore, in animal models of nervous system diseases, it is frequently necessary to precisely locate and harvest brain tissue, such as from the hippocampus, substantia nigra, or other neural nuclei. Ensuring the integrity of the obtained rat or mouse brain tissue is therefore extremely important.

[0003] Currently, there are several methods for obtaining brain tissue from laboratory animals: Method 1: After anesthetizing rats or mice, the head of the rat or mouse is cut off with scissors. The skin on the top of the skull is cut open to expose the skull. Tissue scissors and bone forceps are used to cut the skull little by little from the foramen magnum to expose the brain tissue. The cranial nerves are cut with small scissors, and the brain tissue is removed. Method 2: After anesthetizing rats or mice, tissue scissors are used to cut the connection between the skull and the cervical vertebrae. The skin on the top of the skull is cut along the sagittal suture. The head of the tissue scissors is inserted into the foramen magnum and cuts the skull towards the left eye socket. The same operation is performed on the right side. Then, the frontal bone between the eye socket and the eye socket is cut horizontally. The left hand holds hook forceps and inserts them into the eye socket to fix the skull. The right hand holds curved forceps to directly clamp the bone at the foramen magnum. The skull is lifted from bottom to top to expose the brain tissue. The brain tissue is pushed upward from the cerebellum with forceps. The cranial nerves are cut with small scissors, and the brain tissue is removed. Method 3: After anesthetizing and euthanizing the rats or mice, use tissue scissors to cut the connection between the skull and the cervical vertebrae. Then, cut the skin of the top of the skull along the sagittal suture and clean the fascia on the top of the skull. Using tissue scissors, cut the occipital bone from the foramen magnum of the rat or mouse along the sagittal suture to the V-shaped point. Using curved hemostats, vertically puncture the frontal bone at a point 0.5-0.8 cm from the anterior fontanelle to the base of the skull along the extension direction of the sagittal suture. At this point, the forceps of the curved hemostat enter the inside of the rat or mouse skull. Due to the thickness of the forceps, the parietal bone of the rat or mouse will be directly opened and divided into left and right parts along the sagittal suture. Then, use the curved hemostats to pry the parietal bone open. After the brain tissue of the rat or mouse is fully exposed, use small scissors to cut the connection between the brain tissue and the nerves at the base of the skull; remove the brain tissue.

[0004] However, all of the above methods for obtaining brain tissue have the following drawbacks:

[0005] (1) It takes a long time. The average time for rats is 10-15 minutes, and the average time for mice is 4-6 minutes. A batch of animal experiments usually involves 100 or more rats or mice. Therefore, multiple researchers are often needed to carry out brain tissue sampling at the same time, which wastes laboratory manpower.

[0006] (2) The skulls of rats or mice are very hard. Using bone forceps or tissue scissors to destroy the skull to obtain brain tissue is very laborious, which affects the efficiency of the experiment and will inevitably affect or even damage the integrity of the brain tissue, thus affecting the subsequent location and sampling of brain tissue.

[0007] (3) It requires a high level of proficiency from the experimenters, which is not conducive to beginners learning. Summary of the Invention

[0008] The purpose of this disclosure is to provide a method for obtaining the brain of laboratory animals. This method can effectively avoid the presence of other tissues in the sampled brain tissue and ensure the integrity of the sampled brain tissue. Furthermore, this method has a short brain extraction time, which improves experimental efficiency.

[0009] To achieve the above objectives, this disclosure provides a method for extracting the brain from an experimental animal, the method comprising the following steps:

[0010] S1. Cut along the skin cutting line on the top of the skull of the euthanized experimental animal to expose the skull bones.

[0011] S2. Take the line connecting the eyes as the nasal bone cutting line, and cut along the nasal bone cutting line to break the nasal bone.

[0012] S3. Extend one end of the sagittal suture to the cervical vertebrae cut point and the other end of the sagittal suture to the nasal bone cut point to form a skull cutting line. Perform a cutting process along the skull cutting line until the skull is broken.

[0013] S4. Along the gap where the skull is broken, lift 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.

[0014] S5. Separate the neural connections between the brain tissue and the base of the skull, and place the experimental animal's head upside down. The brain tissue will detach from the skull under the influence of gravity, thus obtaining the complete brain tissue of the experimental animal.

[0015] Optionally, in step S1, the skin cutting line is formed by connecting the midpoint of the line connecting the two eyes and the midpoint of the line connecting the two ears of the experimental animal and extending to the cervical spine skin cutting point.

[0016] Optionally, step S3 further includes: placing the inner edge of one side of the scissors blade against the first endpoint of the skull cutting line, placing the inner edge of the other side of the scissors blade against the second endpoint of the skull cutting line, and performing a cutting process along the skull cutting line until the skull is broken.

[0017] Optionally, the number of cuts in the slicing process is 2-3.

[0018] Optionally, step S4 further includes: inserting the tips of the blades on both sides of the scissors into the middle of the gap in the skull, and then opening the scissors to lift 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.

[0019] Optionally, the insertion depth of the two blade tips of the scissors into the middle of the gap in the skull is 1-2 mm.

[0020] Optionally, in step S1, the method further includes:

[0021] The experimental animal was anesthetized, and then the fur at the cervical vertebrae of the experimental animal was cut open, and the spinal cord of the experimental animal in the neck was severed.

[0022] Optionally, the method further includes: after anesthetizing the experimental animal, performing blood sampling from the abdominal aorta or enucleating the eyeballs of the experimental animal.

[0023] Optionally, the experimental animals are selected from rodent experimental animals;

[0024] Preferably, the rodent experimental animals are selected from experimental rats and / or experimental mice.

[0025] Alternatively, the extracted intact brain tissue can be stored and fixed in a paraformaldehyde solution.

[0026] Through the above technical solution, this disclosure provides a method for obtaining the brain of experimental animals. This method can effectively avoid the presence of other tissues in the sampled brain tissue and ensure the integrity of the sampled brain tissue. Moreover, this method has a short brain extraction time, improves experimental efficiency, effectively reduces the number of experimental personnel required, and saves experimental personnel's time.

[0027] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0028] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0029] Figure 1 This document details the steps for removing the brains from experimental rats and mice.

[0030] Figure 2 This refers to the integrity of brain tissue obtained from experimental rats and mice using different methods at the same sampling time.

[0031] Figure 3 These are the sampling time for experimental rats and 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.

[0032] Figure 4 This is a top view of the mouse skull.

[0033] Figure 5 This is a top view of the mouse's head and its positional relationship with the brain tissue.

[0034] Figure 6 This is a top view of the mouse's head and the cut lines on its skin.

[0035] Figure 7 This is a top view of a mouse lying down, showing the point where its cervical spine was severed.

[0036] Explanation of reference numerals in the attached figures

[0037] 1. Skin cutting line; 2. Nasal bone cutting line; 3. Skull cutting line; 4. Cervical vertebrae cutting point. Detailed Implementation

[0038] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0039] like Figure 1 and 4 As shown in Figure 7, this disclosure provides a method for extracting the brain from an experimental animal, the method comprising the following steps:

[0040] S1. Cut along the skin cutting line 1 on the top of the skull of the euthanized experimental animal to expose the skull bones.

[0041] S2. Take the line connecting the eyes as the nasal bone cutting line 2, and cut along the nasal bone cutting line 2 to break the nasal bone.

[0042] S3. Extend one end of the sagittal suture to the cervical vertebrae cut 4 and the other end of the sagittal suture to the nasal bone cut to form a skull cutting line 3. Cut along the skull cutting line 3 until the skull is broken.

[0043] S4. Along the gap where the skull is broken, lift 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.

[0044] S5. Separate the neural connections between the brain tissue and the base of the skull, and place the experimental animal's head upside down. The brain tissue will detach from the skull under the influence of gravity, thus obtaining the complete brain tissue of the experimental animal.

[0045] In this disclosure, the method can effectively avoid the presence of other tissues in the sampled brain tissue and ensure the integrity of the sampled brain tissue; moreover, the method can greatly shorten the time required for brain retrieval experiments in rats and mice, saving the physical strength of experimental personnel; the average time for retrieval of rat brain tissue in this disclosure is 4 minutes / rat and the average time for retrieval of mouse brain tissue is 2 minutes / rat, which greatly improves the speed of brain tissue retrieval, effectively reduces the number of experimental personnel required, saves experimental personnel's time, and improves experimental efficiency.

[0046] In step S2 of this disclosure, "the location where the inner corners of the eyes meet" refers to the location of the line connecting the inner corners of the eyes and its vicinity. This can be the line connecting the inner corners of the eyes, or a line near and parallel to the line connecting the inner corners of the eyes. These lines can all serve as the nasal bone cutting line. Cutting along the nasal bone cutting line makes the subsequent step of opening the skull easier.

[0047] In one embodiment of this disclosure, in step S1, the skin cutting line 1 is formed by connecting the midpoint of the line connecting the two eyes and the midpoint of the line connecting the two ears of the experimental animal and extending to the cervical spine skin cutting point.

[0048] In one embodiment of this disclosure, step S3 further includes: placing the inner edge of one side of the scissors blade against the first endpoint of the skull cutting line 3, and placing the inner edge of the other side of the scissors blade against the second endpoint of the skull cutting line 3, and performing a slicing process along the skull cutting line 3 until the skull is broken. 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 vertebrae where it is cut, and this connection point can serve as either the first or second endpoint of the skull cutting line; the other end of the sagittal suture extends to the nasal bone where it is cut, and this connection point can serve as either the second or first endpoint of the skull cutting line. When performing the slicing process, care should be taken to ensure that the blade tip is not at the same level as the brain tissue, but rather higher than the horizontal space where the brain tissue is located, to avoid the blade tip being inserted too deeply and damaging the brain tissue, thus affecting the integrity of the sample. Preferably, the number of slicing operations is 2-3 times. In this 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.

[0049] In one embodiment of this disclosure, step S4 further includes: inserting the tips of the blades on both sides of the scissors into the middle of the skull slit, and then opening the scissors to lift 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. Preferably, the insertion depth of the tips of the blades into the middle of the skull slit is 1-2 mm.

[0050] In this disclosure, "left side" refers to the side of the mouse's left body or left eye, and "right side" refers to the side of the mouse's right body or right eye.

[0051] In step S5 of this disclosure, placing the experimental animal's head upside down means placing the side with the intact brain tissue exposed downwards. The neural connection between the brain tissue and the base of the skull refers to the tiny channel between the skull bone marrow and the meninges, which is a white connection point visible to the naked eye.

[0052] In this disclosure, scissors can be used for cutting and slicing, and the scissors can be pointed surgical scissors and / or ordinary scissors.

[0053] In one embodiment of this disclosure, step S1 further includes:

[0054] The experimental animal was anesthetized, and then the fur at the cervical vertebrae of the experimental animal was cut open, and the spinal cord of the experimental animal in the neck was severed.

[0055] In the above embodiments, such as Figure 7 As shown, the skin and spinal cord of the cervical vertebrae of the experimental animal are cut in a direction parallel to the line connecting the eyes; this step can euthanize the experimental animal and create a cervical vertebra cut site 4 and a cervical skin cut site at the cervical vertebrae.

[0056] According to this disclosure, the method further includes: after anesthetizing the experimental animal, performing blood sampling from the abdominal aorta or enucleating the eyeballs. Complete blood sampling avoids endogenous interference from intracerebral blood flow in subsequent detection of brain tissue pathology and biochemical indicators.

[0057] According to this disclosure, the experimental animals are selected from rodent experimental animals. Preferably, the rodent experimental animals are selected from experimental rats and / or experimental mice.

[0058] In one embodiment of this disclosure, the extracted intact brain tissue is fixed in a paraformaldehyde solution. The mass concentration of paraformaldehyde in the paraformaldehyde solution is 4%.

[0059] The present disclosure is further described in detail below through examples.

[0060] Experimental rats: 28 male SPF-grade SD rats, 8 weeks old, 160-200g; purchased from Beijing Vital River Laboratory Animal Co., Ltd.

[0061] Laboratory mice: 32 male SPF-grade db / db mice, 8 weeks old, 20-25g; purchased from Jiangsu Cyagen Biotech Laboratory Animal Co., Ltd.

[0062] This experiment was approved by the Laboratory Animal Welfare and Ethics Committee of the Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences. The ethics numbers for the rat and mouse experiments were 2024B085 and 2024B133, respectively. The rats and mice were housed together at the Laboratory Animal Center of the Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences. The animal rooms were clean, bright, and well-ventilated, with a temperature of 18–22°C and a humidity of 45%–55%.

[0063] Example 1

[0064] S1. Anesthetize the rats, collect blood from the abdominal aorta and the eyeballs, then cut the fur at the cervical spine position perpendicular to the rat's cervical spine and cut the connection between the rat's skull and cervical spine.

[0065] After the rat was euthanized, the midpoint of the line connecting the rat's eyes and the midpoint of the line connecting its ears was connected and extended to the point 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 open along the skin cutting line 1 to expose the skull bones.

[0066] S2. Take the line connecting the eyes as the nasal bone cutting line 2, and cut along the nasal bone cutting line 2 to break the nasal bone.

[0067] S3. Extend one end of the sagittal suture to the cervical vertebrae cut 4, and extend the other end of the sagittal suture to the nasal bone cut to form a skull cutting line 3. Place the inner edge of one side of the scissors against the first end of the skull cutting line 3, and place the inner edge of the other side of the scissors against the second end of the skull cutting line 3. Make cuts along the skull cutting line 3 2-3 times until the skull is broken.

[0068] S4. Insert the tips of the scissors into the middle of the gap in the skull (insertion depth of 1mm), then open the scissors to lift the left side of the skull to the left and the right side of the skull to the right, so as to expose the complete brain tissue.

[0069] S5. Separate the neural connections between the brain tissue and the base of the skull, and place the rat's head upside down so that the brain tissue detaches from the skull under the influence of gravity; thus obtaining the complete brain tissue of the rat.

[0070] Example 2

[0071] S1. Anesthetize the mice, collect blood from the abdominal aorta and the eyeballs, then cut the fur at the cervical spine position perpendicular to the cervical spine and cut the connection between the skull and the cervical spine.

[0072] After euthanizing the mouse, connect the midpoint of the line connecting the mouse's eyes and the midpoint of the line connecting the two ears and extend it to the point where the skin of the cervical spine was cut to form a skin cutting line 1. Use scissors to cut open the skin on the top of the mouse's skull along the skin cutting line 1 to expose the skull bones.

[0073] S2. Take the line connecting the eyes as the nasal bone cutting line 2, and cut along the nasal bone cutting line 2 to break the nasal bone.

[0074] S3. Extend one end of the sagittal suture to the cervical vertebrae cut 4, and extend the other end of the sagittal suture to the nasal bone cut to form a skull cutting line 3. Place the inner edge of one side of the scissors against the first end of the skull cutting line 3, and place the inner edge of the other side of the scissors against the second end of the skull cutting line 3. Make cuts along the skull cutting line 3 2-3 times until the skull is broken.

[0075] S4. Insert the tips of the scissors into the middle of the gap in the skull (insertion depth of 1mm), then open the scissors to lift the left side of the skull to the left and the right side of the skull to the right, so as to expose the complete brain tissue.

[0076] S5. Separate the neural connections between the brain tissue and the base of the skull, and place the mouse head upside down so that the brain tissue detaches from the skull under the influence of gravity; thus obtaining the complete brain tissue of the mouse.

[0077] Comparative Example 1

[0078] After anesthetizing the rat, the rat's head was cut off with scissors. The skin of the top of the skull was cut open in a direction perpendicular to the line connecting the eyes to expose the skull. Using tissue scissors and bone forceps, the skull was cut open little by little from the foramen magnum toward the frontal bone to expose the brain tissue. The cranial nerves were cut with small scissors and the brain tissue was removed.

[0079] Comparative Example 2

[0080] After anesthetizing the mice, the rats' skulls were cut off with scissors. The skin on the top of the skull was cut open in a direction perpendicular to the line connecting the eyes to expose the skull. Using tissue scissors and bone forceps, the skull was cut open little by little from the foramen magnum toward the frontal bone to expose the brain tissue. The cranial nerves were cut with small scissors and the brain tissue was removed.

[0081] Comparative Example 3

[0082] After anesthetizing the rats, use tissue scissors to cut the connection between the skull and cervical vertebrae, cut the skin of 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, cutting to the eye socket. Repeat the same operation on the right side. Then cut the frontal bone between the rat's orbit and eye sockets horizontally. Use hook forceps in the left hand to insert into the rat's eye socket to fix the skull, and use curved forceps in the right hand to 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, cut the cranial nerves with small scissors, and remove the brain tissue.

[0083] Comparative Example 4

[0084] After anesthetizing the mice, use tissue scissors to cut the connection between the skull and cervical vertebrae, cut the skin of 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, cutting to the eye socket. Repeat the same operation on the right side. Then cut the frontal bone between the mouse's eye sockets horizontally. Use hook forceps in the left hand to insert into the mouse's eye socket to fix the skull, and use curved forceps in the right hand to 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, cut the cranial nerves with small scissors, and remove the brain tissue.

[0085] Comparative Example 5

[0086] After anesthetizing and euthanizing the rats, the connection between the skull and cervical vertebrae was severed using tissue scissors. Then, the skin of the top of the skull was cut along the sagittal suture, and the fascia on the top of the skull was cleaned. Using tissue scissors, the occipital bone was cut from the foramen magnum along the sagittal suture to the V-shaped point. Using curved hemostats, the frontal bone was vertically pierced to the base of the skull at a point 0.8 cm from the anterior fontanelle to the frontal bone along the extension of the sagittal suture. At this point, the forceps of the curved hemostats entered the inside of the rat's skull. Due to the thickness of the forceps, the rat's parietal bone was directly pried open and divided into left and right parts along the sagittal suture. The parietal bone was then pried open again with the curved hemostats. After the rat's brain tissue was fully exposed, the connection between the brain tissue and the nerves at the base of the skull was severed using small scissors. The brain tissue was then removed.

[0087] Comparative Example 6

[0088] After anesthetizing and euthanizing the mice, the connection between the skull and cervical vertebrae was severed using tissue scissors. Then, the skin on the top of the skull was cut along the sagittal suture, and the fascia on the top of the skull was cleaned. Using tissue scissors, the occipital bone was cut from the foramen magnum along the sagittal suture to the V-shaped point. Using curved hemostats, the frontal bone was vertically pierced to the base of the skull at a point 0.6 cm from the anterior fontanelle to the frontal bone along the extension of the sagittal suture. At this point, the forceps of the curved hemostats entered the inside of the mouse's skull. Due to the thickness of the forceps, the parietal bone of the mouse was directly pried open and divided into left and right parts along the sagittal suture. The parietal bone was then pried open again with curved hemostats. After the mouse's brain tissue was fully exposed, the connection between the brain tissue and the nerves at the base of the skull was severed using small scissors. The brain tissue was then removed.

[0089] The data from Examples 1-2 and Comparative Examples 1-6 were statistically analyzed for "sampling time under the same brain tissue integrity", "brain tissue integrity under the same sampling time", and "brain tissue to body weight ratio under the same sampling time". The integrity of the extracted brain tissue and the above data are as follows: Figure 2 and 3 As shown, the method disclosed herein requires a shorter sampling time for the same brain tissue integrity, achieves a higher brain tissue integrity score for the same sampling time, and has a higher brain tissue to body weight ratio, with significant differences and statistical significance.

[0090] The preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0091] 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, this disclosure will not describe the various possible combinations separately.

[0092] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A method for extracting the brain from an experimental animal, characterized in that, The method includes the following steps: S1. Anesthetize the experimental animal, then cut the fur at the cervical vertebrae of the experimental animal and sever the spinal cord in the neck of the experimental animal. Cut the skin on the top of the skull along the cut line (1) of the skull of the euthanized experimental animal to expose the skull bones. S2. Take the line connecting the eyes as the nasal bone cutting line (2), and cut along the nasal bone cutting line (2) to break the nasal bone. S3. Extend one end of the sagittal suture to the cervical vertebrae cut (4) and the other end of the sagittal suture to the nasal bone cut to form a skull cutting line (3). Cut along the skull cutting line (3) until the skull is broken. S4. Along the gap where the skull is broken, lift 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. S5. Separate the neural connections between the brain tissue and the base of the skull, and place the experimental animal's head upside down. The brain tissue will detach from the skull under the influence of gravity, thus obtaining the complete brain tissue of the experimental animal. In step S1, the skin cutting line (1) is formed by connecting the midpoint of the line connecting the two eyes and the midpoint of the line connecting the two ears of the experimental animal and extending to the cervical vertebrae where the skin is cut.

2. The method according to claim 1, wherein, Step S3 further includes: placing the inner edge of one side of the scissors against the first end of the skull cutting line (3), placing the inner edge of the other side of the scissors against the second end of the skull cutting line (3), and making a cut along the skull cutting line (3) until the skull is broken.

3. The method according to claim 2, wherein, The number of cuts in the slicing process is 2-3.

4. 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 of the gap in the skull, and then opening the scissors to lift 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.

5. The method according to claim 4, wherein, Insert the tips of the scissors into the middle of the gap in the skull, with an insertion depth of 1-2mm.

6. The method according to claim 5, wherein, The method further includes: after anesthetizing the experimental animal, performing blood sampling from the abdominal aorta or enucleating the eyeballs of the experimental animal.

7. The method according to any one of claims 1-6, wherein, The experimental animals were selected from rodent experimental animals.

8. The method according to claim 7, wherein, The rodent experimental animals were selected from experimental rats and / or experimental mice.

9. The method according to claim 1, wherein, The extracted intact brain tissue was stored and fixed in paraformaldehyde solution.

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