Construction method of animal myocardial ischemia models of different degrees and surgical instrument box

Abstract

The invention discloses a construction method of animal myocardial ischemia models of different degrees and a surgical instrument box. The construction method comprises the following steps: extruding the heart of an experimental animal out of a body, and positioning coronary left anterior descending branch; during ligation, needle heads with different diameters are used as cushion needles to be placed between a ligature and a blood vessel, and the cushion needles are pulled out after ligation to form different degrees of vascular stenosis; and retracting the heart, exhausting and suturing to obtain different degrees of myocardial ischemia models. The method is simple to operate, small in wound, and capable of reducing the death rate of animals, saving time and improving the success rate and repeatability of the model; the matched surgical instrument box ensures the consistency of ligation degrees through standardized instruments, solves the problem of model instability caused by operation differences, can also establish a model for simulating ICM progressive pathological characteristics, and provides a tool for exploring pathogenesis and formulating treatment strategies.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of modeling in medical basic research, and specifically to a method for constructing animal myocardial ischemia models of different degrees and a surgical instrument box. BACKGROUND

[0002] Cardiovascular disease is one of the leading causes of death among adults worldwide, with ischemic heart disease (IHD) accounting for nearly half of the deaths. IHD is mainly caused by reduced blood flow in the coronary arteries, leading to insufficient oxygen supply to the myocardium, and further triggering coronary artery disease, which is often manifested as chest pain and may be accompanied by difficulty breathing. However, many patients, especially women and those with less than 75% coronary artery stenosis, often exhibit atypical symptoms or no symptoms, which can easily lead them to miss the best treatment opportunity and worsen their condition. Ischemic cardiomyopathy (ICM), as a special or late manifestation of IHD, is characterized by myocardial cell damage, necrosis, and fibrosis caused by long-term myocardial ischemia, which further leads to significant structural remodeling and functional decline of the heart, and is the main cause of heart failure in developed countries. Although there have been advances in the treatment of acute myocardial infarction (MI), which has improved the survival rate of patients during the acute phase, the incidence and prevalence of ICM continue to rise. In basic research, animal models, especially mouse disease models, provide important tools for the study of myocardial injury mechanisms and potential treatment methods. Currently, the commonly used IHD animal models mainly include myocardial infarction models induced by permanent ligation of the left anterior descending coronary artery and ischemia-reperfusion (I / R) injury models induced by temporary ligation of the left anterior descending coronary artery. These models play an important role in the study of myocardial injury mechanisms and treatment methods.

[0003] However, existing IHD animal models have significant shortcomings in simulating the pathological characteristics of clinical ICM. First, they cannot simulate the myocardial ischemia gradient changes caused by different degrees of coronary artery stenosis in the clinic. Existing MI models and I / R models mainly simulate the pathological state of complete coronary artery occlusion or reperfusion after transient ischemia, and cannot reflect the myocardial ischemia caused by different degrees of coronary artery stenosis, such as 50% and 75% stenosis, which are common in the clinic. This limits the applicability of these models in the study of ICM disease progression. Second, the model construction method is complex and has a high mortality rate. The traditional method of opening the chest and ligating the left anterior descending branch of the coronary artery has a large surgical trauma and a long operation time, and the postoperative mortality rate of mice is high, which affects the repeatability of the experiment and the stability of the model. In addition, the lack of standardized tools also leads to inconsistent operations. There is no standardized surgical instrument in the existing technology, such as a specific size needle, and there are large differences in the ligation force and needle selection among different researchers or laboratories, resulting in poor consistency and comparability of the model. Finally, existing models are mainly used for acute MI or I / R research, and cannot simulate the progressive pathological characteristics of ICM, such as myocardial fibrosis, ventricular remodeling, and chronic heart failure caused by long-term mild ischemia.

[0004] To address the above problems, some measures have been taken to improve the existing technology. In order to simulate the myocardial ischemia gradient changes caused by different degrees of coronary artery stenosis, some researchers have tried to adjust the ligation force or use different sizes of ligation lines to simulate different degrees of stenosis. However, this method is difficult to accurately control the degree of stenosis, and the results are greatly affected by the experience of the operator. In order to reduce the complexity and mortality rate of model construction, some researchers have adopted minimally invasive surgical methods, such as using small incisions or endoscopic assisted surgery, to reduce surgical trauma and operation time. Although these methods have reduced the mortality rate to some extent, they still require high surgical skills and experience. In order to solve the problem of lack of standardized tools, some researchers have started to use standardized surgical instruments, such as specific size needles and ligation lines, to improve the consistency and comparability of the model. However, the popularity of these standardized tools is still limited, and there are still differences in operations among different laboratories. In order to simulate the progressive pathological characteristics of ICM, some researchers have tried to extend the observation time or use multiple ischemia-reperfusion methods to simulate the process of long-term mild ischemia. However, these methods still cannot completely simulate the complex pathological process of ICM.

[0005] Although some measures have been taken to improve the IHD animal model in the prior art, there are still many problems. First, the myocardial ischemia gradient change caused by different degrees of coronary artery stenosis in the clinic cannot be accurately simulated, which is still a key factor limiting the study of the disease progression of ICM. Second, although minimally invasive surgical methods and standardized surgical instruments are used, the complexity and mortality of model construction are still high, and the operation differences between different laboratories still exist, affecting the repeatability of the experiment and the stability of the model. Finally, the existing model still cannot completely simulate the progressive pathological characteristics of ICM, such as myocardial fibrosis, ventricular remodeling and chronic heart failure, which limits its application in the study of the pathogenesis and therapeutic targets of ICM. Therefore, developing an animal model that can accurately reflect the pathological progression of clinical ICM is still a problem to be solved at present. SUMMARY

[0006] In order to solve the problems of the traditional open chest myocardial infarction model in the prior art, such as large trauma, high mortality, long time and poor stability, and the difficulty in simulating different degrees of stenosis of coronary artery in patients with ischemic cardiomyopathy in clinic, the present application provides a method for constructing a different degree animal myocardial ischemia model and a surgical instrument box, which can accurately simulate different degrees of stenosis of coronary artery in clinic, clearly present the ischemia gradient change, and provide a more realistic model. The operation is simple, the trauma is small, the mortality of experimental animals can be significantly reduced, the time can be saved, the success rate of model construction and repeatability can be improved. The surgical instrument box uses standardized instruments to ensure consistent ligation degree, solves the problem of unstable model caused by operation difference. It can also establish a model simulating the progressive pathological characteristics of ICM, providing a powerful tool for exploring the pathogenesis and developing strategies.

[0007] To achieve the above object, the present application provides the following technical scheme: a method for constructing a different degree animal myocardial ischemia model, the specific steps are as follows: The heart of the experimental animal is extruded out of the body, and the position of the left anterior descending coronary artery is located; When ligating the left anterior descending coronary artery, a pad needle with different diameters is used as a pad needle between the ligature and the blood vessel, and the pad needle is slowly pulled out after ligation to form different degrees of vascular stenosis; The heart is returned to the chest cavity, the air in the chest cavity is extruded out, and it is sutured to obtain a different degree animal myocardial ischemia model.

[0008] Further, the position of the left anterior descending coronary artery is located at the left anterior descending branch 1.5mm-2mm below the left atrial appendage.

[0009] Further, different diameter pad needles are used to construct different degree animal myocardial ischemia model, specifically: The myocardial infarction model is constructed to simulate 100% occlusion, without using a pad needle, and directly ligating; Construct a severe myocardial ischemia model, simulate 75%~99% occlusion, use 34G pad needle, after ligation slowly pull out the pad needle; Construct a moderate myocardial ischemia model, simulate 50%~74% occlusion, use 30G pad needle, after ligation slowly pull out the pad needle.

[0010] Further, the experimental animal adopts the healthy SPF level mouse of 20g~25g in weight.

[0011] Further, the specific steps that the experimental animal heart is extruded to the outside of the body are as follows: Anesthetize the experimental animal, and fix its four limbs; Cut an incision on the left side of the sternum of the experimental animal, and bluntly separate muscles layer by layer to expose the intercostal space; Find the largest intercostal space under the field of vision on the chest of the experimental animal, and perform a distraction operation on the intercostal space, so that the heart is in the middle position for subsequent operation; Extrude the heart of the experimental animal from the chest cavity through the distracted intercostal space, and ensure that the heart can be completely clamped at the incision.

[0012] Further, the length of the incision is 1cm~1.5cm, and 6-0 ligation line and 4-0 suture line are used.

[0013] The application provides a severe myocardial ischemia model, which is constructed by the above method, and specifically comprises the following steps: Anesthetize the experimental animal, and fix its four limbs; Cut an incision on the left side of the sternum of the experimental animal, and bluntly separate muscles layer by layer to expose the intercostal space; Find the largest intercostal space under the field of vision on the chest of the experimental animal, and perform a distraction operation on the intercostal space, so that the heart is in the middle position for subsequent operation; Extrude the heart of the experimental animal from the chest cavity through the distracted intercostal space, and ensure that the heart can be completely clamped at the incision. Position the left anterior descending branch of the coronary artery; When ligating the left anterior descending branch of the coronary artery, use a 34G needle as a pad needle between the ligation line and the blood vessel, and slowly pull out the pad needle after ligation to form different degrees of blood vessel stenosis; Return the heart to the chest cavity, extrude the air in the chest cavity, and suture, to obtain a severe myocardial ischemia model with 75%~99% occlusion.

[0014] The application provides a severe myocardial ischemia model, which is constructed by the above method, and specifically comprises the following steps: Anesthetize the experimental animal, and fix its four limbs; Cut an incision on the left side of the sternum of the experimental animal, and bluntly separate muscles layer by layer to expose the intercostal space; Find the largest intercostal space in the chest of the experimental animal under the field of view, and perform a distraction operation on the intercostal space to place the heart in an intermediate position for subsequent operations; Squeeze the heart of the experimental animal out of the chest cavity through the distracted intercostal space, while ensuring that the heart can be completely clamped at the incision; Position the left anterior descending branch of the coronary artery; Use a 30G needle as a pad needle between the ligature and the blood vessel when ligating the left anterior descending branch of the coronary artery, and slowly pull out the pad needle after ligation to form different degrees of blood vessel stenosis; Return the heart to the chest cavity, squeeze out the air in the chest cavity, and suture to obtain a moderate myocardial ischemia model with 50%-74% occlusion.

[0015] The application also provides a myocardial infarction model constructed by the above method, specifically comprising: Anesthetize the experimental animal and fix its limbs; Make an incision on the left side of the sternum of the experimental animal, bluntly separate the muscles layer by layer, and expose the intercostal space; Find the largest intercostal space in the chest of the experimental animal under the field of view, and perform a distraction operation on the intercostal space to place the heart in an intermediate position for subsequent operations; Squeeze the heart of the experimental animal out of the chest cavity through the distracted intercostal space, while ensuring that the heart can be completely clamped at the incision; Position the left anterior descending branch of the coronary artery; Directly ligate the left anterior descending branch of the coronary artery; Return the heart to the chest cavity, squeeze out the air in the chest cavity, and suture to obtain a myocardial infarction model with 100% occlusion.

[0016] The application also provides a surgical instrument box for constructing experimental animal myocardial ischemia models of different degrees; the surgical instrument box comprises 10cm ophthalmic scissors, a needle holder with shearing function, a curved hemostat, a curved ophthalmic forceps, 6-0 ligature, 4-0 ligature, a 30G pad needle, and a 34G pad needle, wherein: The ophthalmic scissors are used to cut a 1cm-1.5cm surgical incision on the left side of the sternum of the experimental animal; The needle holder is used for surgical suturing; The curved hemostat is used for clamping hemostasis; The curved ophthalmic forceps are used for bluntly separating the muscles in front of the experimental animal; The 6-0 ligature is used to ligate the left anterior descending branch of the coronary artery of the experimental animal; The 4-0 ligature is used to suture the skin incision of the experimental animal; The 30G pad needle is used to be placed between the ligature and the blood vessel when ligating the left anterior descending branch of the coronary artery, and is pulled out after ligation to form a 50%-74% blood vessel stenosis to construct a moderate myocardial ischemia model; 34G pad needle is used for placing between ligature and blood vessel when ligating left anterior descending branch of coronary artery, and after ligating, the pad needle is pulled out to form 75%-99% blood vessel stenosis, and a severe myocardial ischemia model is constructed.

[0017] Compared with the prior art, the present application has at least the following beneficial effects: The present application provides a method for constructing different degrees of animal myocardial ischemia model, and when ligating the left anterior descending branch of the coronary artery, the pad needle is placed between the ligature and the blood vessel, and after pulling out, a gradient blood vessel stenosis can be formed, which accurately corresponds to the different conditions of patients with clinical ischemic cardiomyopathy. Compared with the traditional open chest model which can only realize single occlusion effect, this method can clearly show the gradient change of ischemia, so that the constructed model is closer to the actual pathological characteristics of the clinic, and provides an experimental carrier with more reference value for subsequent exploration of pathogenesis and development of treatment strategies, effectively solving the core problem that the existing model is disconnected with the clinical scene.

[0018] The method of the present application focuses on the key steps: extracorporeal positioning of the heart, pad needle assisted ligation, and heart replacement suture. The complex process of chest exposure and tissue separation in traditional open chest surgery is omitted, and the operation threshold is lower, so that even less experienced experimental personnel can quickly master it. At the same time, the simplified operation process greatly shortens the operation time and reduces the stress reaction of experimental animals during the operation; and without opening the chest cavity in a large area, the trauma range is small, which can significantly reduce the risk of postoperative infection and mortality of experimental animals. On the data level, the success rate of model construction is improved, and the repeatability is enhanced, solving the problem of low success rate and large fluctuation of results caused by the complexity of traditional models.

[0019] The method is not limited to a single animal type and ischemia degree, and can be flexibly expanded by adjusting the diameter of the pad needle and adapting to different weight experimental animals. For example, for common experimental animals such as mice and rats, only the operation details need to be adjusted; and according to the research needs, whether to use the pad needle or select different diameter pad needles, the full range model from myocardial infarction (100% occlusion) to severe and moderate myocardial ischemia can be constructed. This high adaptability allows the model to meet the needs of different research directions, providing more comprehensive tool support for ischemic cardiomyopathy related research and breaking the limitation of single application scene of traditional models.

[0020] Further, the present application clearly positions the left anterior descending branch of the coronary artery at a position 1.5mm to 2mm below the left atrial appendage, which has clear anatomical markers, avoids position deviation caused by traditional positioning relying on experience, ensures that each ligation is applied to the same blood vessel segment, and reduces the instability problem of the model caused by positioning differences. Further, the present application establishes a precise correspondence system between the diameter of the trocar and the degree of ischemia: without using a trocar, a myocardial infarction model with 100% occlusion is simulated, a 34G trocar corresponds to a severe ischemia model with 75% to 99% occlusion, and a 30G trocar corresponds to a moderate ischemia model with 50% to 74% occlusion. This quantitative standard makes the degree of ischemia controllable and measurable, solving the problem of ambiguous ischemia degree and inability to accurately grade in traditional models. At the same time, further limiting the experimental animals to 20g to 25g healthy SPF mice, the uniform animal specifications eliminate interference factors such as body weight and health status, further ensuring experimental reproducibility; refining the heart extrusion steps and incision length (1cm to 1.5cm), suture specifications (6-0 ligature, 4-0 suture), making the operation process more instructive, reducing human error, and promoting the development of model construction towards standardization and normalization, providing a unified basis for multicenter experimental data comparison.

[0021] The present application also provides a surgical instrument box for implementing the above modeling method, which provides strong support for the construction of animal myocardial ischemia models of different degrees through specialized and standardized instrument configuration, effectively solving the problem of operation differences caused by the clutter and poor adaptability of traditional instruments. First, the instrument configuration completely matches the full-process requirements of model construction: 10cm ophthalmic scissors precisely adapt to 1cm to 1.5cm left thoracic incisions, needle holders with cutting function consider suture and suture handling, curved hemostats and curved ophthalmic forceps meet the precise operation of hemostasis and muscle separation, respectively, 6-0 and 4-0 ligature precisely correspond to coronary artery ligation and skin suture scenarios, and 30G and 34G trocars directly match moderate and severe ischemia model construction. This on-demand configuration design avoids the trouble of temporarily piecing together different instruments in traditional experiments, improving operation convenience. Second, all instrument specifications are uniform and clear, such as trocar diameter fixed at 30G and 34G, and ligature specifications at 6-0 and 4-0, ensuring that the instrument parameters used by different experimenters and different experimental batches are consistent, eliminating problems such as unstable ligation degree and inconsistent operation results caused by instrument differences from the tool level. In addition, the integrated instrument box design facilitates instrument storage, carrying and sterilization, reduces the risk of instrument loss or contamination, ensures the standardization of the experimental process, and further improves the reliability and repeatability of experimental results. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 Flow chart of the construction method of the present application for different degree myocardial ischemia models in mice; Figure 2This invention provides cardiac function testing data from mouse models of myocardial ischemia with varying degrees of severity. Figure 3 For the detection of ischemic area of ​​the heart in mouse models of myocardial ischemia of different degrees in this invention; Figure 4 Surgical instruments and instrument boxes for constructing mouse myocardial ischemia models of different degrees according to the present invention. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0024] This invention provides a method for constructing animal models of myocardial ischemia of different degrees, and includes a surgical instrument kit, as detailed below: 1) Preoperative preparation First, the hair on the chest of the experimental animal is removed to expose the surgical field. The experimental animal is then anesthetized and its limbs are fixed.

[0025] 2) Surgical procedure Step 1, Chest Opening: Use ophthalmic scissors to make a 1cm to 1.5cm incision on the left side of the sternum. Use ophthalmic forceps to bluntly separate the muscles layer by layer to expose the intercostal spaces.

[0026] Step 2, Exposing the Heart: Using needle forceps, insert them into the fourth intercostal space and quickly squeeze out the heart of the experimental animal.

[0027] Step 3: Ligation of the coronary artery: Locate the left anterior descending coronary artery (the left anterior descending coronary artery located 1.5mm~2mm below the left atrial appendage). Select needles of different diameters from the surgical instrument box as pad needles. Ligate the left anterior descending coronary artery with 6-0 ligation suture. After tying the knot, remove the needle. Different diameter needles can construct ischemia models of different degrees.

[0028] In experimental settings for constructing myocardial ischemia models in laboratory animals, the pad needle is a tool used to simulate different degrees of coronary artery stenosis. It is a specialized experimental instrument. Specifically, when ligating the left anterior descending coronary artery, a needle of different diameters (e.g., 34G, 30G) is placed between the ligation suture and the blood vessel. After ligation, the pad needle is slowly withdrawn, thus creating different degrees of vascular stenosis (e.g., 75%–99% or 50%–74% occlusion simulation). This design allows for precise control of the degree of coronary artery stenosis, helping researchers construct different models of severe and moderate myocardial ischemia, and providing a standardized experimental tool for myocardial ischemia-related research.

[0029] Step 4: Return the heart to the chest cavity and expel the air from the chest cavity.

[0030] Step 5: Suturing and disinfection: Suture the skin with 4-0 sutures, and finally disinfect with alcohol. After the experimental animal wakes up, put it back into the cage and feed it normally. Observe the postoperative recovery of the experimental animal.

[0031] 3) Model Detection The area of ​​myocardial ischemia was detected by TTC staining, and cardiac function was detected at different time points after surgery by echocardiography of experimental animals.

[0032] Example 1 This embodiment provides a method for constructing a mouse model of myocardial ischemia that can simulate different degrees of coronary artery stenosis, offering a more ideal experimental tool for related research. The specific surgical procedure and test results are as follows: I. Specific Surgical Procedure (I) Preoperative preparation like Figure 4 As shown, the procedure was performed using a surgical instrument kit (which included 10cm ophthalmic scissors, a needle holder with cutting function, curved hemostatic forceps, curved ophthalmic forceps, 6-0 ligation sutures, 4-0 ligation sutures, 30G pad needles, and 34G pad needles).

[0033] Healthy SPF mice weighing 20g-25g were selected, and hair was removed from the chest area one day before surgery using depilatory cream. Figure 1 A). To provide a clear view for subsequent surgical procedures.

[0034] (II) Anesthesia, fixation, and disinfection Connect the mouse anesthesia machine and anesthetize the mice with 2% isoflurane. After the mice are in a suitable state of anesthesia, place them in a supine position and fix their limbs to ensure stability during the operation. Then, disinfect the surgical area with 75% alcohol. Figure 1 B), to reduce the risk of infection.

[0035] (iii) Cut open the skin Use ophthalmic scissors to cut open the skin on the left side of the mouse's chest, making an incision of about 1-1.5 cm. After cutting the skin, disinfect it again with 75% alcohol. Figure 1 C), further ensuring a sterile surgical environment.

[0036] (iv) Separate the muscles to expose the intercostal spaces Use a pointed needle holder to bluntly dissect the superficial and deep muscles of the chest layer by layer. Exercise caution during the procedure to avoid damaging surrounding tissues and blood vessels, and fully expose the intercostal spaces. Figure 1 (D) This prepares for the subsequent extrusion of the heart.

[0037] (v) Squeezing out the heart Using the right hand, insert a curved needle holder into the mouse's fourth intercostal space (the largest intercostal space in the field of view), and spread the needle holder so that the heart is positioned between the two heads of the needle holder. Figure 1 (E, F) to provide suitable space and support for squeezing out the heart. Next, use the left index finger and thumb to squeeze out the mouse heart, ensuring it is completely lodged in the incision. During this process, be gentle to avoid pneumothorax. Figure 1 G).

[0038] (vi) Positioning and ligation Observe the course of the coronary arteries, locate the left atrial appendage, and use 6-0 sutures to pass through the left anterior descending artery (which primarily supplies blood to the heart and maintains its beating) approximately 2 mm below the left atrial appendage. Figure 1 H).

[0039] Different diameter shims were used for different degrees of myocardial ischemia models: A myocardial infarction (MI) model (simulating 100% occlusion) was constructed by direct ligation without using a shim. A severe myocardial ischemia ICM-34G model (simulating 75%~99% occlusion) was constructed using a 34G shim (0.19mm in diameter), and the shim was slowly removed after ligation. A moderate myocardial ischemia ICM-30G model (simulating 50%~74% occlusion) was constructed using a 30G needle (0.31mm in diameter), and the needle was slowly removed after ligation. The sham control group (Sham mice) underwent the same surgery but were not ligated ( Figure 1 I~K).

[0040] (vii) Returning the heart and expelling gas Quickly return the heart to the chest cavity after surgery, gently squeeze the chest cavity to expel excess air, and avoid pneumothorax. Figure 1 L, M), to ensure the heart is in its normal position within the chest cavity and the pressure within the chest cavity is stable.

[0041] (viii) Suturing, disinfection, and feeding Suture the skin with 4-0 sutures and disinfect with alcohol. Figure 1 (N~P), complete the surgical procedure. After the mouse recovers, return it to its cage and feed it normally, then observe its postoperative recovery.

[0042] II. Results of cardiac function and ischemic area detection in mice Myocardial ischemia area was detected by TTC staining, and cardiac function was assessed at different time points post-surgery using mouse echocardiography. The results of cardiac function and ischemia area measurements in mice are as follows: (a) Cardiac function testing One month after surgery, the heart function of the mice was assessed using small animal ultrasound, and the results were as follows:Figure 2 As shown, the ejection fraction of the heart in the sham-operated group was 70%, while that in the moderate ischemia group (ICM-30G) was approximately 38%, in the severe ischemia group (ICM-34G) it was approximately 24%, and in the myocardial infarction group (MI) it was approximately 19%. The latter three groups showed significant differences compared to the sham group, indicating that different degrees of myocardial ischemia significantly affected cardiac function in mice, and that the more severe the ischemia, the lower the ejection fraction.

[0043] (II) Detection of ischemic area of ​​the heart One month after surgery, the ischemic area of ​​the mouse heart was measured using the TTC staining method, and the results were as follows: Figure 3 As shown, the ischemic area of ​​the heart in mice in the moderate ischemia group (ICM-30G) was approximately 38%, in the severe ischemia group (ICM-34G) it was approximately 46%, and in the myocardial infarction group (MI) it was approximately 53%. The latter three groups showed significant differences compared to the sham group, and there were also significant differences among the latter three groups themselves. This indicates that different ligation methods lead to different degrees of myocardial ischemia in mice, and that the ischemic area is closely related to both the ligation method and the degree of ischemia.

[0044] The surgical procedures and test results described above demonstrate that the mouse myocardial ischemia models of varying degrees constructed in this embodiment can accurately simulate myocardial ischemia under different clinical conditions, providing a reliable experimental model for cardiovascular disease research. Furthermore, by using needles of different diameters, this method can also be applied to rat models.

Claims

1. A method for constructing a model of myocardial ischemia of different degrees in animals, characterized in that, The specific steps are as follows: The heart of the experimental animal is extruded out of the body, and the left anterior descending coronary artery position is located; When ligating the left anterior descending coronary artery, a needle with different diameters is used as a pad needle between the ligature and the blood vessel, and the pad needle is slowly pulled out after ligation to form different degrees of vascular stenosis; The heart is returned to the chest cavity, and the air in the chest cavity is extruded out, and sutured to obtain different degrees of animal myocardial ischemia model.

2. The method according to claim 1, wherein, The left anterior descending coronary artery position is located at the left anterior descending branch 1.5mm-2mm below the left auricle.

3. The method according to claim 1, wherein, Different degrees of animal myocardial ischemia model are constructed using different diameter pad needles, specifically: Construct myocardial infarction model, simulate 100% occlusion, do not use pad needle, directly ligate; Construct severe myocardial ischemia model, simulate 75%-99% occlusion, use 34G pad needle, slowly pull out the pad needle after ligation; Construct moderate myocardial ischemia model, simulate 50%-74% occlusion, use 30G pad needle, slowly pull out the pad needle after ligation.

4. The method according to claim 1, wherein, The experimental animal is a healthy SPF mouse with a body weight of 20g-25g.

5. The method according to claim 1, wherein, The specific steps for extruding the heart of the experimental animal out of the body are as follows: Anesthetize the experimental animal and fix its limbs; Make an incision on the left side of the sternum of the experimental animal, and bluntly separate the muscles layer by layer to expose the intercostal space; Find the largest intercostal space under the field of view on the chest of the experimental animal, and perform a distraction operation on the intercostal space to place the heart in an intermediate position for subsequent operation; Extrude the heart of the experimental animal from the chest cavity through the distracted intercostal space, while ensuring that the heart can be completely clamped at the incision.

6. The method according to claim 5, wherein, The length of the incision is 1cm-1.5cm, and 6-0 ligature and 4-0 suture are used.

7. A model of severe myocardial ischemia, characterized in that, The method of claim 1 is used for construction, specifically: Anesthetize the experimental animal and fix its limbs; Make an incision on the left side of the sternum of the experimental animal, and bluntly separate the muscles layer by layer to expose the intercostal space; Find the largest intercostal space under the field of view on the chest of the experimental animal, and perform a distraction operation on the intercostal space to place the heart in an intermediate position for subsequent operation; Extrude the heart of the experimental animal from the chest cavity through the distracted intercostal space, while ensuring that the heart can be completely clamped at the incision. Locate the left anterior descending coronary artery position; When ligating the left anterior descending coronary artery, a 34G needle is used as a pad needle between the ligature and the blood vessel, and the pad needle is slowly pulled out after ligation to form different degrees of vascular stenosis; Return the heart to the chest cavity, extrude the air in the chest cavity, and suture to obtain a severe myocardial ischemia model with 75%-99% occlusion.

8. A model of severe myocardial ischemia, characterized in that, The method of claim 1 is used for construction, specifically: Anesthetize the experimental animal and fix its limbs; Make an incision on the left side of the sternum of the experimental animal, and bluntly separate the muscles layer by layer to expose the intercostal space; Find the largest intercostal space under the field of view on the chest of the experimental animal, and perform a distraction operation on the intercostal space to place the heart in an intermediate position for subsequent operation; Extrude the heart of the experimental animal from the chest cavity through the distracted intercostal space, while ensuring that the heart can be completely clamped at the incision. Locate the left anterior descending coronary artery position; When ligating the left anterior descending coronary artery, a 30G needle is used as a pad needle between the ligature and the blood vessel, and the pad needle is slowly pulled out after ligation to form different degrees of vascular stenosis; The heart is returned to the chest cavity, the air in the chest cavity is squeezed out, and the incision is sutured to obtain a moderate myocardial ischemia model with 50%-74% occlusion.

9. A myocardial infarction model, characterized by The method of claim 1 is used for construction, specifically: Anesthetize the experimental animal and fix its limbs; Make an incision on the left side of the sternum of the experimental animal, bluntly separate the muscles layer by layer, and expose the intercostal space; Find the largest intercostal space in the field of view on the chest of the experimental animal, and perform a distraction operation on the intercostal space to place the heart in an intermediate position for subsequent operation; Squeeze the heart of the experimental animal out of the chest cavity through the distracted intercostal space, while ensuring that the heart can be completely clamped at the incision; Position the left anterior descending coronary artery; Directly ligate the left anterior descending coronary artery; The heart is returned to the chest cavity, the air in the chest cavity is squeezed out, and the incision is sutured to obtain a myocardial infarction model with 100% occlusion.

10. A surgical instrument case characterized by, It is used for constructing myocardial ischemia models of different degrees in experimental animals; the surgical instrument box includes: 10 cm ophthalmic scissors, needle holder with shearing function, curved hemostatic forceps, curved ophthalmic forceps, 6-0 ligature, 4-0 ligature, 30G trocar needle, and 34G trocar needle; wherein: The ophthalmic scissors are used to cut an incision of 1-1.5 cm on the left side of the sternum of the experimental animal; The needle holder is used for surgical suturing; The curved hemostatic forceps are used for clamping hemostasis; The curved ophthalmic forceps are used for bluntly separating the pectoral muscles of the experimental animal layer by layer; The 6-0 ligature is used to ligate the left anterior descending coronary artery of the experimental animal; The 4-0 ligature is used to suture the skin incision of the experimental animal; The 30G trocar needle is used to place between the ligature and the blood vessel when ligating the left anterior descending coronary artery, and after ligation, it is pulled out to form a 50%-74% vascular stenosis to construct a moderate myocardial ischemia model; The 34G trocar needle is used to place between the ligature and the blood vessel when ligating the left anterior descending coronary artery, and after ligation, it is pulled out to form a 75%-99% vascular stenosis to construct a severe myocardial ischemia model.

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