ECMO-removed artificial uterine animal model and construction method thereof

Abstract

The invention belongs to the technical field of animal models, and particularly relates to an ECMO-removed artificial uterine animal model and a construction method thereof. The animal model comprises an animal maternal body, an in-vitro fetus and an artificial uterus, the fetus is from the animal maternal body, blood circulation is established between the animal maternal body and the fetus, the blood circulation starts from the internal carotid artery of the animal maternal body, is connected to the umbilical vein of the fetus through a pipeline and enters the body of the fetus, and after the fetal circulation, the artificial uterus enters the fetal body. Starting from the fetal umbilical artery, entering the internal jugular vein of the animal maternal body through a pipeline; the fetus is located in the artificial uterus, and the artificial uterus provides a sterile artificial amniotic fluid environment for the fetus and maintains the body temperature of the fetus. According to the method, the ECMO-removed artificial uterine animal model is successfully constructed through the pregnant sheep, and the ECMO-removed artificial uterine animal model is maintained for about 90 minutes at most. A feasible animal model is provided for early surgical treatment of fetal congenital diseases and life maintenance of premature fetuses, and a foundation is laid for future clinical transformation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of animal models, and particularly relates to an ECMO-removed artificial uterus animal model and a construction method thereof. BACKGROUND

[0002] According to statistics of the World Health Organization (Organization, W.H., Birth defects surveillance training: Facilitator's guide. 2016: World Health Organization.), about 6% of newborns have congenital malformations or congenital diseases every year, and some serious congenital malformations can even cause stillbirths. For example, congenital cystic adenomatoid malformation (CCAM) is a relatively common type of lung airway malformation, which can be screened by ultrasound or CT in the second trimester of pregnancy. Most congenital cystic adenomatoid malformations are usually asymptomatic during pregnancy, but a small number of fetuses have large lesions that can compress surrounding tissues or organs, causing various complications, and even fetal edema or death in severe cases (Wei Zihao, et al., Analysis of risk factors related to congenital cystic adenomatoid malformation of the lung in fetuses . Chinese Journal of Practical Diagnosis and Treatment, 2023. 37(02): p. 207-210.). In addition to congenital cystic adenomatoid malformation, amniotic band syndrome, pulmonary bronchial lung isolation, congenital diaphragmatic hernia (CDH), congenital high airway obstruction syndrome (CHAOS) and other serious malformations require intrauterine fetal surgery to remove the lesion through a surgical approach to protect the fetus and the mother. However, the risk of uterine rupture, fetal death, surgical complications, early delivery and potential treatment failure of congenital defects after fetal surgery is relatively high, so timely induced abortion is currently recommended for serious malformations (Ruano, R. and B. Vega, Fetal surgery: how recent technological advancements are extending its applications . Expert review of medical devices, 2019. 16(8): p. 643-645.; Maselli, K.M. and A. Badillo, Advances in fetal surgery. Annals of translational medicine, 2016. 4(20).

[0003] In order to solve the problem of surgical intervention for severe fetal diseases during pregnancy, an ECMO (Extracorporeal Membrane Oxygenation) artificial uterus model has been constructed in the prior art. All artificial uterus projects in the world currently use ECMO for oxygenation support (Kuwabara, Y., et al., Development of extrauterine fetal incubation system using extracorporeal membrane oxygenator. Artificial organs, 1987. 11(3): p. 224-227.; Kading, J.C., et al., Tidal Flow Perfusion for the Artificial Placenta: A Paradigm Shift. ASAIO J, 2020. 66(7): p. 796-802.; Usuda, H., et al., Successful use of an artificial placenta to support extremely preterm ovine fetuses at the border of viability. Am J Obstet Gynecol, 2019. 221(1): p. 69 e1-69 e17.), and a circulating pump is needed for auxiliary circulation, which faces many problems.Firstly, the blood oxygenated by ECMO needs to be heparinized anticoagulation, the placental circulation volume is small, the anticoagulant dosage is difficult to adjust, and the risk of serious complications such as spontaneous intracranial hemorrhage is high (Usuda, H., et al., Successful use of an artificial placenta to support extremely preterm ovine fetuses at the border of viability. Am J Obstet Gynecol, 2019. 221(1): p. 69 e1-69 e17.), although there have been some studies in recent years without the use of anticoagulants (Fallon, B.P., et al., Extracorporeal life support without systemic anticoagulation: a nitric oxide-based non-thrombogenic circuit for the artificial placenta in an ovine model. Pediatric Research, 2023: p. 1-9.), but the progress is slow, and there are few successful reports. Secondly, the connection of multiple pipelines greatly increases the risk of blood stream infection, and long-term extracorporeal support requires the use of large doses of antibiotics, which is a potential risk to fetal development. In addition, the ECMO system is expensive, which has formed a certain obstacle to the promotion of artificial uterus. SUMMARY

[0004] The present application is to solve the problems of long-term anticoagulation, use of large doses of antibiotics, and high cost of traditional ECMO artificial uterus. A set of feasible ECMO-free artificial uterus animal model is designed and constructed using pregnant goats. The model constructed by the present application is a feasible animal model for early surgical treatment of fetal congenital diseases and life support of preterm fetuses, and lays a foundation for clinical transformation.

[0005] The present application specifically adopts the following technical solutions: The present application provides an ECMO-free artificial uterus animal model, which comprises an animal mother, an ex vivo fetus and an artificial uterus, the fetus is a mid-pregnancy fetus from the animal mother, a blood circulation is established between the animal mother and the fetus, the blood circulation starts from the internal carotid artery of the animal mother, is connected to the umbilical vein of the fetus through a pipeline, enters the fetus, after fetal circulation, starts from the umbilical artery of the fetus, enters the internal jugular vein of the animal mother through a pipeline; the fetus is located in the artificial uterus, and the artificial uterus provides a sterile artificial amniotic fluid environment for the fetus and maintains the body temperature of the fetus.

[0006] In a further aspect, the second trimester refers to a gestational age of 60% to 80% of the total gestational age.

[0007] In a further aspect, the animal is a pregnant goat, and the fetus is a fetal goat at a gestational age of 90 to 120 days.

[0008] Goat is an ideal choice for the construction of animal models in the present application. On the one hand, the body size and weight of pregnant goat are moderate, and the pregnancy is mainly 1 to 3 fetuses, and the physiological development process of fetal goat is highly similar to that of human; on the other hand, the blood type is compatible among individuals within the goat species, so there is no need to worry about the occurrence of hemolysis or agglutination reaction after the circulation of the mother and the fetus is connected (Wang Zhenfang, et al., Autologous transfusion and cross matching test of experimental goat. Chinese Journal of Veterinary Medicine, 2018. 54(11): p. 111-112.). The gestational age of goat is generally about 150 days, and the pregnant goat used in the present application has a gestational age of 90 to 120 days, which corresponds to about 20 to 25 weeks of human pregnancy, and this is also the time window for the diagnosis of most congenital diseases. For example, the diagnosis of congenital cystic adenomatoid malformation of the lung is generally made at 18 to 22 weeks of gestation, and the lesion tissue will rapidly progress and grow at 20 to 26 weeks, and has a certain potential for malignant transformation (Niu Yujie and Cen Limicro, Analysis of the influencing factors of fetal congenital cystic adenomatoid malformation of the lung and the influence of postnatal surgical treatment on pregnancy outcome . Chinese Journal of Fertility and Health, 2020. 31(6): p. 535-538.). Therefore, early surgical intervention is necessary for similar congenital diseases. The artificial uterus provides a relatively stable platform for early surgical treatment of congenital diseases, and has less impact on the mother, and also provides a safer environment similar to the mother for premature infants of about 24 weeks, which is expected to increase the survival rate of premature infants and further improve the survival limit of premature infants. In the future, for pregnant women with pregnancy complications that need to be treated, such as patients with malignant tumors, the artificial uterus can safely transfer the fetus to the outside of the body, allowing the pregnant woman to start treatment of the complication earlier. At the same time, the artificial uterus also provides a new idea for multifetal pregnancy reduction (MPR), and in the future, pregnant women with multiple pregnancies no longer need to face the choice, and can retain the fetus in vitro and develop maturely.

[0009] In a further aspect, the artificial uterus comprises a box-shaped shell, and each of the upper and lower shells has an interface for circulating water bath liquid. The interior of the artificial uterus is a circulating water bath, the fetus is immersed in the artificial amniotic fluid and is wrapped by a sterile protective cover, and the sterile protective cover is located in the artificial uterus and maintains the body temperature of the fetus by the external circulating water bath.

[0010] In a further aspect, the artificial amniotic fluid is Ringer's solution. In particular, the artificial amniotic fluid has a temperature of 37℃, and the circulating water bath has a temperature of 38.5℃.

[0011] The present application provides a method for constructing an ECMO-free artificial uterus animal model, comprising the following steps: A: Select a pregnant animal mother, and implant a blood vessel sheath tube into the internal carotid artery and internal jugular vein of the animal mother through surgery, connect an extension tube, and seal the tube for standby use; B: Perform abdominal surgery to remove the fetus, fill the sterile protective cover with artificial amniotic fluid, and transfer the fetus into the artificial amniotic fluid, dissociate the umbilical artery and umbilical vein in the umbilical cord, and implant them into the blood vessel sheath tube and connect the extension tube, connect the umbilical artery with the internal jugular vein of the mother and the internal carotid artery of the mother with the umbilical vein, ligate and cut the original umbilical cord near the mother, and ligate the sterile protective cover, and transfer the whole fetus to the artificial uterus; C: Close the mother's uterus and abdominal cavity.

[0012] The present application has the following advantages: The artificial uterus model of the present application aims to solve the problem of fetal malformation surgery which requires surgical intervention, and can also be applied to the treatment of extremely premature fetuses. The primary goal of the artificial uterus model is to provide short-term support for the fetus, ensure stable vital signs during surgery, and meet the short-term development needs after surgery. The long-term goal is to solve the problem of treatment of extremely premature fetuses and ensure normal maturation of fetal lungs. The ultimate goal is to achieve complete separation from the mother's growth and development.

[0013] The artificial uterus model constructed by the present application is independent of ECMO. The design without ECMO makes the maintenance of the model itself unnecessary to use anticoagulants for a long time, thereby avoiding a series of complications caused by abnormal coagulation function, such as spontaneous pulmonary hemorrhage, cerebral hemorrhage, or thrombus-related diseases. Similarly, the design without ECMO avoids many infection opportunities, and the mature immune system of the mother can provide a physiological barrier for the entire system without the need for a large amount of antibiotics for long-term maintenance. In addition, the independence from ECMO greatly reduces the construction cost of the entire model and significantly reduces the maintenance difficulty, laying a foundation for the large-scale popularization of the model in the future.

[0014] The present application successfully constructs an ECMO-free artificial uterus animal model in a pregnant sheep, and maintains it for about 90 minutes. The present application provides a feasible animal model for early surgical treatment of fetal congenital diseases and life support for premature fetuses, and lays a foundation for future clinical transformation. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1: Schematic diagram of ECMO decoupled artificial uterus animal model; wherein the blood circulation is started from the internal carotid artery of the ewe (the red pipeline shown in the figure), connected to the umbilical vein of the fetal lamb to enter the fetal lamb body, after the fetal circulation, started from the umbilical artery of the fetal lamb, through the pipeline (the blue pipeline shown in the figure) into the internal jugular vein of the ewe. The right cube in the figure is the artificial uterus designed by the application, which includes a box-shaped shell, the whole shell is made of PVC and is bonded by waterproof glue, and each of the upper and lower shells has an interface for circulating water bath liquid, the inside is a 38.5℃ circulating water bath, the fetal lamb is immersed in the artificial amniotic fluid and is wrapped in a sterile medical protective cover, and the outside of the sterile protective cover is continuously circulated in the water bath to maintain the body temperature of the fetal lamb.

[0016] Figure 2 : Construction of ECMO decoupled artificial uterus; A: Carotid artery and vein cannulation of the ewe, wherein the internal carotid artery is shown below the picture (red arrow shows the blood flow direction), and the internal jugular vein is shown above the picture (blue arrow shows the blood flow direction).

[0017] B: Separation of umbilical cord artery and vein, at this time the fetal lamb on the left side of the picture has been placed in a sterile medical protective cover and immersed in artificial amniotic fluid, and the ewe is shown on the right side of the picture.

[0018] C: Umbilical cord artery and vein puncture cannulation, after separating the umbilical cord blood vessels, the same method of puncture cannulation and fixation is used as the carotid blood vessels.

[0019] D: Place the fetal lamb in the artificial uterus, and connect it to the ewe through the external pipeline via the umbilical cord blood vessels, and the arterial blood and venous blood can be distinguished by color in the figure.

[0020] Figure 3 : Vital signs of the ewe. The figure is the monitoring of the vital signs of the ewe during the construction of the model, the time point 0 represents the start of the maternal and fetal circulation and connection, the negative time represents before the connection, and the positive time represents after the connection. The blood pressure and heart rate of the ewe remained stable during the construction of the model. The error bar represents the standard deviation.

[0021] Figure 4 Observation results of fetal heart rate and other indicators.

[0022] A: Observe the fetal heart rate by ultrasound and record the heart rate, and the heart rate shown in the figure is 160 times per minute.

[0023] B: Umbilical vein blood pressure change curve, time point 0 represents the start of maternal and fetal circulation and connection. The umbilical vein blood flow flows from the maternal carotid artery to the fetal lamb. The error bar represents the standard deviation.

[0024] C: Fetal heart rate and umbilical artery blood pressure change curve, umbilical artery blood flow flows from the fetal lamb to the maternal jugular vein. The error bar represents the standard deviation. DETAILED DESCRIPTION

[0025] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0026] Embodiment 1 1. Materials and methods 1.1 Experimental animals: Four pregnant goats in the middle of pregnancy (pregnancy period of 90-120 days) with a body weight of 35-45 kg were selected. Animal feeding and experiments were performed in accordance with the regulations of Zhengzhou University for experimental animal feeding and use and the "Guidelines on the Treatment of Laboratory Animals" formulated by the Ministry of Science and Technology of the People's Republic of China. The experiment has been approved by the Research and Clinical Trial Ethics Committee of the First Affiliated Hospital of Zhengzhou University and the Life Science Ethics Review Committee of Zhengzhou University.

[0027] 1.2 Establishment of animal model 1.2.1 Anesthesia and preoperative preparation The experimental animals were fasted for 12 hours before operation, but not deprived of water. After the ear was prepared, a retention needle was inserted into the ear vein, connected to a three-way tube, and midazolam 0.4 mg / kg was injected intravenously. When the experimental sheep moved slowly and steadily, the muscles were relaxed, and the corneal reflex was dull, it was considered that the anesthesia induction was successful. Intravenous combined anesthesia was performed, and arterial puncture was performed on the ear artery to monitor arterial pressure. The animal was placed in a supine position on the operating bed, and the tongue forceps were taken out, and the oximeter was connected to the monitor. The neck was prepared and disinfected, and the skin was cut longitudinally under the thyroid cartilage for about 8 cm, and the tissue was bluntly separated layer by layer to expose the trachea. Tracheostomy was performed between 2-3 cartilage rings below the thyroid cartilage, and the tracheal tube was inserted to connect the respirator, with a depth of 5 cm. The respirator assisted ventilation. The limbs and abdomen were prepared and disinfected, the number of fetal goats and body position were determined by ultrasound, and the fetal heart beat was observed. The electrode plate was pasted, and the conventional disinfection and draping were performed.

[0028] The use of anesthetic drugs during the above-mentioned anesthesia is as follows: In acute experiments, ketamine and rocuronium are administered via intravenous infusion through the marginal ear vein; in chronic experiments, remifentanil is added to this regimen. The baseline dosage is: ketamine 200 mg / h, rocuronium 40 mg / h, and remifentanil 2 mg / h. Ketamine is a general anesthetic with strong analgesic and sedative effects. It does not affect uterine contractions or neonatal respiration and is commonly used in cesarean sections under general anesthesia. Remifentanil, an ultra-short-acting opioid, is often used during the induction of general anesthesia for cesarean sections. At a dosage of 0.5–1.0 µg / kg·min, its effects on the neonate are minimal. Rocuronium is a non-depolarizing muscle relaxant with rapid onset and good muscle relaxation. It is a high molecular weight and low lipid-soluble substance, making it difficult to cross the placental barrier and having minimal impact on the neonate. Remifentanil has a half-life of 1.3 minutes and is rapidly hydrolyzed in the body by non-specific esterases, without accumulation, and has almost no inhibitory effect on neonatal respiration.

[0029] 1.2.2 Neck vascular catheterization The tissue surrounding the trachea was bluntly dissected at the tracheotomy site to expose the internal carotid artery and internal jugular vein. Vascular sheaths (RS*A50K10SQ, Terumo Corporation, Japan) were inserted into each sheath and connected to extension tubes (extracorporeal circulation tubing for an artificial heart-lung machine, Xi'an Xijing Medical Supplies Co., Ltd.). The tubes were then sealed with heparinized saline.

[0030] 1.2.3 Abdominal surgery A midline longitudinal laparotomy was performed to expose the uterus. A monopolar high-frequency electrosurgical unit was used to open the uterine muscle layer and the amniotic sac. Tissue forceps were used to lift the uterus upwards to prevent amniotic fluid loss. Figure 2 A). Re-examine the number, position, and condition of the fetuses to determine which fetuses need to be transferred and free them from the amniotic sac. Overlap two layers of sterile protective sheaths (80*60cm medical sterile protective sheaths, Jiangxi 3L Medical Products Group Co., Ltd.) and fill them with artificial amniotic fluid at 37°C (using Ringer's solution). Cover the fetus's head with a damp gauze to prevent breathing and transfer the fetus into the artificial amniotic fluid. Disconnect the umbilical artery and umbilical vein from the fetus's umbilical cord. Figure 2 B), insert the vascular sheaths and connect the extension tubes ( Figure 2 C), use heparinized saline to seal the tube. Connect the umbilical artery to the maternal internal jugular vein and the maternal internal jugular artery to the umbilical vein through a three-way valve. Ligate and cut the original umbilical cord near the maternal end. Tie two layers of sterile protective sheaths separately, and transfer the fetal sheep whole to an artificial uterus water bath. Figure 2 (D) Maintain a water bath temperature of 38.5°C, slightly higher than the artificial amniotic fluid temperature, to maintain the artificial amniotic fluid temperature. After transferring the fetal sheep to the artificial uterus, close the maternal uterus layer by layer, return the intestines, and temporarily close the abdominal cavity using cloth clamps.

[0031] 1.2.4 Postoperative Management The abdomen was closed by suturing the abdominal wall layer by layer after the operation. Cefozolin 1 g was used for intravenous infusion to prevent infection during the operation, and cefozolin 1 g was used for intravenous infusion twice a day for three days after the operation, and flurbiprofen axetil was used for intravenous infusion to relieve pain. After all the operations were completed, the anesthesia was gradually stopped until the experimental animals had spontaneous respiration and reacted to the anti-respiratory machine, and the tracheal cannula was removed, and the tracheal incision was sutured layer by layer.

[0032] 1.2.5 Kindness endpoint After the operation was completed and the relevant data was recorded, the anesthesia was stopped, and the ewe was raised alone after waking up, and the fetal lamb was placed in an artificial uterus outside the body, and the growth and development of the fetal lamb and the state of the ewe were recorded every day. It is expected that the fetal lamb can survive and continue to grow and develop in the artificial uterus outside the body after the operation, and be artificially delivered after maturation, and the ewe can survive normally. If serious complications occur, the experiment is terminated immediately, and euthanasia is performed: 20 ml of 15% potassium chloride solution is injected into the experimental animal in the internal jugular vein under anesthesia, and the blood pressure and heart rate of the experimental animal are observed until the heart stops beating spontaneously, and the carcass of the experimental animal is incinerated as medical waste.

[0033] 1.3 Observation index The maternal vital signs were continuously monitored, including heart rate, invasive arterial pressure, blood oxygen saturation, end-tidal carbon dioxide concentration, etc. After the fetal lamb was transferred to the artificial uterus, ultrasonic monitoring was used to monitor the fetal heart beat and umbilical cord blood pressure. At the end of the experiment, it was observed whether the fetal lamb could survive normally after being artificially delivered, and if the experiment was terminated due to serious complications, the fetal lamb was dissected, and the maturity of the fetal lamb was evaluated according to the fetal lung and fetal brain.

[0034] 1.4 Statistical method Data analysis was performed using R4.3.1, ggplot2 package was used for plotting, t test or Mann-Whitney U test was used for comparison, and α=0.05 was used as the test standard.

[0035] 2. Results All 4 pregnant ewes (referred to as the 1st, 2nd, 3rd, and 4th cases in the order of the experiment) were successfully modeled, and the ewes survived for a long time after the operation, of which 1 was subjected to hysterectomy due to postoperative uterine hemorrhage; 3 of the pregnant ewes were multiple pregnancies, and the fetal lambs not placed in the artificial uterus continued to develop after the experiment and were delivered, and survived normally after birth.

[0036] After the fetal lamb was placed in the artificial uterus, the vital signs of the ewe were observed for 30 minutes, and the heart rate and blood pressure were stable Figure 3As shown, blood oxygen saturation and end-tidal carbon dioxide levels remained stable throughout, and the fetal heartbeat of the lamb was normal within the artificial uterus. Figure 4 A), the umbilical cord vein blood pressure is stable ( Figure 4 (B, C). The mean blood pressure and heart rate of ewes before and after the establishment of the parallel cycle were analyzed by Mann-Whitney U test and t test, respectively. There was no statistically significant difference (p>0.05), as shown in Table 1. The observation time in the 3rd and 4th experiments lasted for 90 minutes.

[0037] Table 1. Average blood pressure and heart rate of ewes before and after establishing parallel circulation. Before parallelization After parallelization p Heart rate (BPM) 111.1±15.6 105.8±11.44 0.200 Mean pressure (mmHg) 91[87.75, 98.33] 89.83[83.75, 94.17] 0.196 The core concept of the ECMO-free artificial uterus animal model is to connect the mother and fetus in parallel in the circulatory system, aiming to fully utilize the mother's life support for the fetus and meet the fetus's needs for oxygen, carbon dioxide metabolism, and nutritional support. In this invention, the animal model connects the mother's carotid artery to two fetal umbilical veins (two veins are freed and catheterized twice in the fetal umbilical cord each time), delivering oxygen- and nutrient-rich arterial blood into the fetal circulation via the inferior vena cava. The maternal arterial pressure is higher than the umbilical vein pressure, creating the hemodynamic force from the mother to the fetus. The fetal umbilical artery originates from two internal iliac arteries and connects to the mother through a sheath. The umbilical artery pressure is generally 50 mmHg, significantly higher than the maternal central venous pressure of 4–12 cmH2O; therefore, fetal heartbeat becomes the primary driving force for this circulatory pathway. After the mother and fetus were connected in parallel, the maternal arterial pressure decreased slightly, but this was not statistically significant, indicating that the construction of this model had little impact on the maternal circulatory system. Furthermore, the remaining fetal lambs in the uterus developed normally and were delivered after the experiment, surviving long-term, further demonstrating that this model had minimal impact on the mother's original physiological functions. In the first two experimental animals with constructed artificial uteruses, the fetal circulation was successfully maintained for 30 minutes after connection with the mother, while in the third and fourth experimental animals, the maternal and fetal circulation was maintained for up to 90 minutes.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An ex-ECMO artificial uterus animal model, characterized in that, The animal model comprises an animal mother, an ex vivo fetus and an artificial uterus, the fetus is a mid-pregnancy fetus from the animal mother, a blood circulation is established between the animal mother and the fetus, the blood circulation is initiated from the internal carotid artery of the animal mother, connected to the umbilical vein of the fetus via a pipeline into the fetus, after the fetal circulation, initiated from the umbilical artery of the fetus, connected to the internal jugular vein of the animal mother via a pipeline; the fetus is located in the artificial uterus and the artificial uterus provides a sterile artificial amniotic fluid environment for the fetus and maintains the body temperature of the fetus.

2. The de-ECMOed artificial uterus animal model of claim 1, wherein, The mid-pregnancy refers to a process of 60% to 80% of the gestation period.

3. The ECMO off human uterine animal model of claim 1, wherein, The animal mother is a pregnant goat, and the fetus is a fetal goat with a gestation period of 90 to 120 days.

4. The de-ECMOed artificial uterus animal model of claim 1, wherein, The artificial uterus comprises a box-shaped shell, and an interface for circulating water bath liquid is left on the shell, the inside of the artificial uterus is a circulating water bath, the fetus is immersed in the artificial amniotic fluid and wrapped by a sterile protective cover, the sterile protective cover is located in the artificial uterus and the fetal body temperature is maintained by the external circulating water bath.

5. The de-ECMOed artificial uterus animal model of claim 1, wherein, The artificial amniotic fluid is Ringer's solution.

6. The de-ECMOed artificial uterus animal model of claim 1, wherein, The temperature of the artificial amniotic fluid is 37℃, and the temperature of the circulating water bath is 38.5℃.

7. The method of constructing an ECMO-deprived artificial uterus animal model according to any one of claims 1 to 6, characterized in that, The method comprises the following steps: A: select a mid-pregnancy animal mother, place a blood vessel sheath in the internal carotid artery and internal jugular vein of the animal mother by surgery, connect an extension tube, seal the tube for standby; B: abdominal surgery to remove the fetus, fill the artificial amniotic fluid in the sterile protective cover, and transfer the fetus to the artificial amniotic fluid, separate the umbilical artery and umbilical vein in the umbilical cord, and place them in the blood vessel sheath and connect the extension tube, connect the umbilical artery to the internal jugular vein of the mother and the internal carotid artery of the mother to the umbilical vein, ligate and cut the original umbilical cord near the mother, ligate the sterile protective cover, and transfer the whole fetal goat to the artificial uterus; C: close the mother's uterus and abdominal cavity.

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