Construction method of newborn bronchial lung dysplasia model

Abstract

The invention relates to the technical field of biology, and particularly discloses a construction method of a newborn bronchial lung dysplasia model. The newborn bronchial pulmonary dysplasia model obtained by the method is a non-invasive model, and compared with mechanical ventilation, invasive operation is needed, the operability for maintaining high oxygen is high, and no harm is caused to animals; moreover, the construction method provided by the invention belongs to complete simulation of clinical operation, the success rate of preparing the model by using the same clinical operation is relatively high when the premature infant inhales high oxygen to cause bronchial lung dysplasia in clinic, and the operation is not performed in the previous large animal model; therefore, the premature infant is simulated by using the early cesarean pig, the clinical operation is simulated by inhaling the high-concentration oxygen, the method belongs to a mechanical-trauma-free mode, and the clinical simulation degree is very high.

Description

Technical Field

[0001] The present application relates to the field of biotechnology, and in particular to a method for constructing a neonatal bronchopulmonary dysplasia model. Background Art

[0002] Bronchopulmonary dysplasia (BPD) is a chronic lung disease that occurs in premature infants. It is caused by prenatal and postnatal factors that impair the normal development of immature lungs, including premature birth, genetic factors, growth restriction, mechanical trauma, oxygen toxicity, infection and inflammation. Its main histopathological features are simplified alveolar structure and abnormal pulmonary vascularization.

[0003] In recent years, with the improvement of neonatal intensive care technology, the survival rate of premature infants has increased, and the incidence of BPD has increased significantly. The mortality rate and complication rate of premature infants with BPD are significantly increased. Surviving children have an increased risk of developing chronic respiratory diseases (such as asthma, chronic obstructive pulmonary disease, etc.), cardiovascular diseases, gastrointestinal diseases, and neurological development problems, including cerebral palsy, developmental delay, and reduced IQ scores, and other multi-organ system diseases, which may even continue into childhood and adulthood. Therefore, BPD is a disease that persists from the fetus to adulthood. Due to the lack of a fundamental treatment for BPD, it has placed a huge economic and mental burden on society and families. Therefore, there is an urgent need to construct an animal model that simulates clinical human BPD to explore the pathogenesis and new treatment strategies of BPD.

[0004] In previous studies, scientists have constructed corresponding BPD models based on the pathogenesis of BPD, such as constructing genetic background model animals, simulating intrauterine infection and inflammation models, and using mechanical ventilation or hyperoxia induction. Mechanical ventilation and hyperoxia induction are commonly used methods to create BPD models in mice, rats, and rabbits.

[0005] Mechanical ventilation is an invasive method that uses tracheotomy and intubation to induce organ damage. It is difficult to operate in small animals, and invasiveness also brings challenges to the success rate and mortality of large animals. Hyperoxia induction is a non-invasive method. Currently, mechanical ventilation and / or hyperoxia are used to make BPD models mainly in mice and rabbits. Among them, the lung development cycle, immune system and metabolism of mice and rats are quite different from those of humans, and there are limitations. However, alveolar development has already begun in full-term rabbits after birth, which cannot reflect the premature immaturity of human anatomy or function. The mortality rate of premature rabbits is high, and the BPD model of premature rabbits lacks standardization. There is also a lack of research on the development of pulmonary blood vessels, so there is controversy about the BPD model of premature rabbits.

[0006] Non-human primates (apes, chimpanzees, baboons, monkeys, etc.) among model animals are highly similar to humans in terms of physiological anatomy, cognitive ability, social complexity, etc., and their genetic material is highly homologous. However, due to their small number, high price, long breeding cycle, difficulty in breeding, and ethical issues, there is currently a lack of large animal models that highly simulate human premature BPD.

[0007] With the continuous development of the field of life sciences, pigs, as model animals, have cardiovascular, respiratory, metabolic and gastrointestinal systems similar to those of humans, and are docile and easy to tame. They can be used in the study of human-related diseases and have made great contributions to improving human health. They have been recognized by medical regulatory agencies around the world, including the U.S. Food and Drug Administration (FDA).

[0008] Since pig lung development and disease course are similar to those of humans, they are suitable as models for simulating human BPD. In addition, miniature pigs are rich in resources, small in size, easy to reproduce, have high survival rates, stable genetic traits, and are similar to humans in genetics, anatomical structure, organ size, nutritional metabolism, and physiological and biochemical characteristics, and have broad application prospects. However, the traditional pig lung dysplasia model is a caesarean section pig, which spontaneously develops lung dysplasia. This model relies on the pig's own development and self-repair ability, resulting in most animals with mild disease, unclear symptoms, poor repeatability, and low modeling success rate. It is not a model for simulating clinical premature infant BPD. Summary of the invention

[0009] The purpose of the present application is to overcome the deficiencies of the above-mentioned prior art and provide a method for constructing a neonatal bronchopulmonary dysplasia model.

[0010] To achieve the above purpose, the technical solution adopted by this application is:

[0011] The present application provides a method for constructing a neonatal bronchopulmonary dysplasia model, comprising the following steps:

[0012] S1. Select premature newborn pigs delivered by cesarean section and place them in an oxygen concentration of 70 ～ 85％ Raised in a breeding environment;

[0013] S2. After 2 to 3 weeks of feeding, the respiratory system function indexes, lung tissue pathology indexes and imaging indexes of the newborn pigs were tested to obtain a neonatal bronchopulmonary dysplasia model.

[0014] In the preliminary experiments of this application, premature pigs were obtained by performing caesarean sections at different ages in advance to determine whether premature pigs can survive, and a series of conditions for modeling neonatal bronchopulmonary dysplasia were explored. For example, pregnant pigs have almost no colostrum after caesarean section and cannot directly feed premature piglets. It is a great challenge to overcome the conditions of artificial feeding to ensure the survival of premature pigs and conduct experiments. How to avoid infection and epidemic prevention during the experiment is another major difficulty.

[0015] The present invention simulates the occurrence conditions of bronchopulmonary dysplasia in human premature infants and neonates, performs modeling through high oxygen induction, explores the setting conditions of oxygen concentration, the length of modeling time, the symptoms of premature pigs during the modeling process, the conditions for successful modeling, and the like. It is the first time to induce premature pigs in a high oxygen feeding environment, thereby achieving the non-invasive requirement and significantly improving the clinical relevance of the neonatal bronchopulmonary dysplasia model.

[0016] Compared with mechanical ventilation which requires invasive operations, this application selects premature newborn pigs delivered by cesarean section and places the newborn pigs in a feeding environment with an oxygen volume percentage concentration of 70-85%. The construction method of this application has a strong operability in maintaining high oxygen and is harmless to animals. This application also uses pigs delivered by cesarean section to simulate premature infants and uses inhalation of high-concentration oxygen to simulate clinical operations, with a high degree of clinical simulation.

[0017] As a preferred embodiment of the method for constructing a neonatal bronchopulmonary dysplasia model described in the present application, in step S1, the volume percentage concentration of oxygen is 80-85%.

[0018] The present application uses different oxygen volume percentage concentrations to induce a bronchopulmonary dysplasia model in premature pig neonates. The symptoms of bronchopulmonary dysplasia in neonates induced by an oxygen volume percentage concentration of 70-75% are relatively mild, the symptoms of bronchopulmonary dysplasia in neonates induced by an oxygen volume percentage concentration of 80-85% are obvious, and the survival rate is about 2 / 3. When an oxygen concentration of 90% is induced in newborn pigs, the symptoms are obvious, and the animals generally die within 2 to 3 days, with a low survival rate, and they cannot be used as model animals for further downstream experiments. This shows that the present application can only use a specific oxygen volume percentage concentration for modeling to obtain a neonatal bronchopulmonary dysplasia model.

[0019] After preliminary research and exploration, it was determined that the best induction conditions were to select premature newborn pigs delivered by cesarean section and to place them in an environment with an oxygen volume percentage concentration of 80-85%. Newborn pigs inhaled oxygen with a volume percentage concentration of 80-85%, breathed 30-50 times / minute, and began to experience shortness of breath (breathing about 60-80 times / minute) at about 1 week, and began to experience significantly worsening shortness of breath (breathing about 80-120 times / minute) at about 2 weeks, accompanied by nasal cyanosis, difficulty feeding, and oxygen dependence. A chest X-ray was performed to confirm lung changes of bronchopulmonary dysplasia in the newborn, and then lung tissue pathology and other examinations were performed. This time point, i.e., the endpoint of the experiment, was 2 to 3 weeks after birth.

[0020] As a preferred embodiment of the method for constructing a neonatal bronchopulmonary dysplasia model described in the present application, in the step S1, the number of days of premature birth is 9 days.

[0021] This application uses full-term newborn pigs, 7-day premature pigs, and 9-day premature newborn pigs delivered by cesarean section for modeling. The neonatal bronchopulmonary dysplasia model was not successfully established under full-term pig hyperoxia conditions, and the neonatal bronchopulmonary dysplasia symptoms and lung damage were not successfully induced in 7-day premature newborn pigs, but the model was successfully established 9 days prematurely. This shows that the number of days of premature birth also has a great impact on the modeling effect. This application finds the time point of the minimum number of successful premature days. The longer the number of premature days, the greater the difficulty of survival.

[0022] As a preferred embodiment of the method for constructing a neonatal bronchopulmonary dysplasia model described in the present application, in step S1, the breeding environment includes: a temperature of 33-35° C. and a humidity of 55%-60%.

[0023] As a preferred embodiment of the method for constructing a neonatal bronchopulmonary dysplasia model described in the present application, in the step S1, soda lime is placed in the breeding environment, and light / darkness is alternated every 12 hours.

[0024] The present application adopts the above-mentioned feeding conditions to better obtain a neonatal bronchopulmonary dysplasia model with high modeling efficiency.

[0025] As a preferred embodiment of the method for constructing a neonatal bronchopulmonary dysplasia model described in the present application, in step S1, an oxygen meter is used to monitor the oxygen volume percentage concentration in the feeding environment in real time, and the oxygen volume percentage concentration is maintained at 80-85%.

[0026] As a preferred embodiment of the method for constructing a neonatal bronchopulmonary dysplasia model described in the present application, the newborn pigs are derived from Bama miniature pigs at 103 to 105 days of gestation.

[0027] Preferably, after the piglet is taken out by cesarean section, it is necessary to resuscitate the piglet and place it in an incubator after it begins to breathe autonomously.

[0028] As a preferred embodiment of the method for constructing a neonatal bronchopulmonary dysplasia model described in the present application, in step S2, the newborn pigs show obvious shortness of breath, breathing at 80 to 120 times per minute, nasal cyanosis, dyspnea, oxygen dependence, and difficulty eating, and the lung tissue pathology indicators and imaging indicators are detected.

[0029] As a preferred embodiment of the method for constructing a neonatal bronchopulmonary dysplasia model described in the present application, in step S2, the lung tissue pathology indicators include radial alveolar counts, alveolitis scores, collagen area ratios and Ashcroft scores.

[0030] This application evaluates the effect of modeling by evaluating inflammatory cell infiltration, pathological changes, and fibrosis of lung tissue through symptom observation, imaging, and pathology.

[0031] Compared with the prior art, this application has the following beneficial effects:

[0032] The present application provides a method for constructing a neonatal bronchopulmonary dysplasia model. The neonatal bronchopulmonary dysplasia model obtained in the present application is a non-invasive model. Compared with mechanical ventilation which requires invasive operations, the model is more operable to maintain high oxygen and is harmless to animals. Moreover, the construction method of the present application completely simulates clinical operations. In clinical practice, premature infants inhale high oxygen, leading to bronchopulmonary dysplasia, with a high success rate. Such model construction operations have not been available in previous large animal models. In addition, the present application uses pigs delivered by premature caesarean section to simulate premature infants, and uses inhalation of high-concentration oxygen to simulate clinical operations, with a high degree of clinical simulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the imaging results of the premature pig bronchopulmonary dysplasia model ( Figure 1 Middle A shows the full-term control group, with clear lung texture; Figure 1 Middle B shows the premature control group, where the lung texture is still clear; Figure 1 Middle C shows the premature hyperoxia group, with increased and thickened lung texture, disordered arrangement, and diffuse strip-like increased density shadows in both lungs with blurred edges);

[0034] Figure 2 This is the H&E staining result of the premature pig bronchopulmonary dysplasia model ( Figure 2 Middle A shows the full-term control group, where the alveoli are basically uniform in size, without obvious collapse and fusion, the alveolar wall structure is intact, and no obvious inflammatory cell infiltration is observed; Figure 2 Middle B shows the premature control group, where the lungs are still in the transition stage from the cystic stage to the alveolar stage, with thick alveolar septa and few secondary septa; Figure 2Middle C shows the premature hyperoxia group, with alveoli of different sizes, alveolar wall rupture and fusion, alveolar septum thickening, alveolar collapse and other lesions coexisting, and inflammatory cell infiltration can be seen in the alveoli and septa);

[0035] Figure 3 This is the Masson staining result of the premature pig bronchopulmonary dysplasia model ( Figure 3 Middle A shows the full-term control group, where very little blue collagen fibers were seen in the alveolar septa; Figure 3 Middle B shows the premature control group, where the alveolar and interlobular septa are widened, and blue collagen fibers can be seen inside; Figure 3 Middle C shows that in the premature hyperoxia group, there is more collagen fiber deposition in the alveolar septum, part of the alveolar cavity is replaced by collagen fibers, the lung tissue structure is deformed, and honeycomb lung appears);

[0036] Figure 4 This is the statistical result of pathology of premature pig bronchopulmonary dysplasia model ( Figure 4 Middle A shows that the radial alveolar count in the premature hyperoxia group was significantly lower than that in the premature control group and the full-term control group (P < 0.0001); Figure 4 Middle B shows that the Szapiel score of alveolitis in the premature hyperoxia group was significantly higher than that in the premature control group (P<0.01) and the full-term control group (P<0.05); Figure 4 Middle C shows that the collagen fiber area ratio in the premature hyperoxia group was significantly higher than that in the premature control group (P<0.01) and the full-term control group (<0.001); Figure 4 Middle D shows that the Ashcroft fibrosis score in the premature hyperoxia group was significantly higher than that in the premature control group and the full-term control group (P < 0.0001) (ns: no significant difference, *: P < 0.05, **: P < 0.01, ***: P < 0.001, ****: P < 0.0001). DETAILED DESCRIPTION

[0037] In order to better illustrate the purpose, technical solutions and advantages of the present application, the present application will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0038] In the following examples and comparative examples, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are all commercially available unless otherwise specified, and the components and raw materials used in each parallel experiment are of the same type.

[0039] Example 1: A method for constructing a neonatal bronchopulmonary dysplasia model

[0040] This embodiment provides a method for constructing a neonatal bronchopulmonary dysplasia model, comprising the following steps:

[0041] 1. Experimental animals: The experimental animals were pregnant Bama miniature pigs and full-term piglets, all provided by Guangdong Mingzhu Biotechnology Co., Ltd.

[0042] 2. Experimental grouping: This part of the experiment was divided into three groups: premature control group, premature hyperoxia group and full-term control group. First, healthy Bama miniature pigs with a clear breeding date were selected. At 103-105 days of pregnancy, cesarean section was performed under general anesthesia to remove the piglets. The newborn pigs were then resuscitated by drying, keeping warm, cleaning the respiratory tract, and inhaling oxygen. After the newborn pigs began to breathe autonomously, they were observed until their breathing was stable and their skin was ruddy. The umbilical cord was disinfected with iodine and then tied, and placed in an incubator to keep warm.

[0043] (1) Premature control group: On the first day after birth, complete lung imaging examination to determine whether there are no infection or other causes of lung lesions. A premature control group is randomly selected from each batch of newborn pigs, anesthetized by intramuscular injection of Zotalitol, and the lungs are isolated for histopathological analysis.

[0044] (2) Premature hyperoxia group: Newborn pigs (premature 7 or 9 days) that were stable after resuscitation were placed in an incubator (temperature 33-35°C, humidity 55%-60%), and medical oxygen was continuously delivered to the incubator. The oxygen concentration in the incubator was monitored in real time using an oxygen meter. The oxygen flow rate was adjusted to maintain the oxygen concentration (oxygen volume percentage concentration) in the incubator at 70%-75%, 80-85%, and 90%, respectively. Soda lime was placed in the incubator to absorb carbon dioxide. The feeding environment was alternating between light and dark every 12 hours, and the respiration of newborn pigs was 30-50 times / minute. The respiration was closely observed. When the piglets showed obvious shortness of breath (about 80-120 times / minute), nasal cyanosis, dyspnea, oxygen dependence, and difficulty in eating, lung imaging examinations were performed. Combined with the clinical manifestations, dyspnea caused by other diseases such as infection was excluded, and the experimental endpoint was set. The piglets were dissected under deep anesthesia, and lung tissue was collected for histopathological analysis.

[0045] (3) Full-term control group: Full-term piglets of the same corrected age as the premature piglets that reached the experimental endpoint were selected for lung imaging examination and dissection under deep anesthesia to collect lung tissue for histopathological analysis.

[0046] 3. Pathological analysis of lung tissue: The collected lung tissues of the full-term control group, premature control group, and premature hyperoxia group piglets were washed with pre-cooled saline and fixed in neutral formalin fixative for 24 hours. The fixed lung lobes were placed in an embedding box and dehydrated according to the procedure. After dehydration, they were embedded in paraffin and the wax blocks were sliced ​​continuously using a tissue slicer and stained according to the operating procedures of the hematoxylin and eosin (H&E) staining kit and the Masson trichrome staining kit, respectively.

[0047] 4. Pathological analysis: The radial alveolar count, alveolar inflammation, fibrosis degree and collagen fiber ratio were compared and analyzed in each group.

[0048] (1) Count of radial alveoli: Several sections were randomly selected from each piglet, and a vertical line was drawn from the center of the respiratory bronchioles to the nearest pleura or fibrous septum. The alveoli on the vertical line were the radial alveoli. Six non-overlapping fields were randomly selected from each section, and the average value was calculated, which was the final radial alveolar count of the piglet, to evaluate the degree of alveolarization.

[0049] (2) Assessment of severity of alveolitis and fibrosis in lung tissue: Several independent sections were selected for each group, and six non-overlapping fields were randomly selected from each section for assessment using the Szapiel (Table 1) and Ashcroft scoring systems (Table 2), respectively.

[0050] Ashcroft score: Fibrosis is scored for areas that occupy more than half of the visual field, and recorded as the main fibrosis level of the visual field. First, determine whether the substance in the visual field is normal or fibrotic. If normal tissue is in the majority, the score is 0; if fibrotic tissue is dominant, the fibrosis level of the area is scored as 1, 3, 5, 7, or 8 in Table 2. If there is any difficulty in making a decision between 1, 3, 5, and 7, give the middle 2, 4, or 6 points.

[0051] (3) Collagen fiber area ratio statistics: Several independent slices were selected from each group, and 6 non-overlapping fields were randomly selected from each slice. The blue collagen fiber area and tissue area were measured using ImageJ software, and the ratio was calculated and then statistically analyzed. The respiratory system function indexes, lung tissue pathology and imaging indexes were tested to evaluate the modeling effect of the porcine BPD model.

[0052] 5. Data statistical analysis: Graphpad Prism software was used for data analysis of the chart data in this embodiment. One-way analysis of variance was used for data that conformed to normal distribution and had equal variance, and t-test was used for pairwise comparison. Non-parametric test was used for data that conformed to normal distribution but had unequal variance or did not conform to normal distribution. P < 0.05 was considered statistically significant.

[0053] Table 1 Szapiel scoring system

[0054]

[0055]

[0056] Table 2 Ashcroft scoring system

[0057]

[0058] The results are as follows:

[0059] The modeling conditions of newborn pigs at different birth times are shown in Table 3.

[0060] The modeling conditions of newborn pigs at different oxygen concentrations are shown in Table 4.

[0061] Table 3

[0062] Full-term pig 7 days premature 9 days premature No BPD symptoms No obvious symptoms and no lung damage Successful induction, 2 / 3 animals survived

[0063] Table 4

[0064] Oxygen concentration 70-75% Oxygen concentration 80~85% Oxygen concentration 90% High survival rate and mild symptoms Modeling success Severe symptoms and low survival rate

[0065] The following is an experimental graph showing the results of a full-term control group, a premature control group, and a premature hyperoxia group (using an oxygen concentration of 80-85%, and newborn pigs that were 9 days premature).

[0066] Reference for imaging results of premature pig bronchopulmonary dysplasia model Figure 1 , Figure 1 Middle A shows the full-term control group, with clear lung texture; Figure 1 Middle B shows the premature control group, where the lung texture is still clear; Figure 1 Middle C shows the premature hyperoxia group, with increased and thickened lung texture and disordered arrangement, and diffuse strip-like increased density shadows with blurred edges in both lungs.

[0067] H&E staining results of premature pig bronchopulmonary dysplasia model Figure 2 , Figure 2 Middle A shows the full-term control group, where the alveoli are basically uniform in size, without obvious collapse and fusion, the alveolar wall structure is intact, and no obvious inflammatory cell infiltration is observed; Figure 2 Middle B shows the premature control group, where the lungs are still in the transition stage from the cystic stage to the alveolar stage, with thick alveolar septa and few secondary septa; Figure 2 Middle C shows the premature hyperoxia group, in which the alveoli vary in size, the alveolar walls are broken and fused, the alveolar septa are thickened, and alveolar collapse coexist. Inflammatory cell infiltration can be seen in the alveoli and septa.

[0068] Masson staining results of premature pig bronchopulmonary dysplasia model Figure 3 , Figure 3 Middle A shows the full-term control group, where very little blue collagen fibers were seen in the alveolar septa; Figure 3 Middle B shows the premature control group, where the alveolar and interlobular septa are widened, and blue collagen fibers can be seen inside; Figure 3 Middle C shows that in the premature hyperoxia group, there is more collagen fiber deposition in the alveolar septa, part of the alveolar cavity is replaced by collagen fibers, the lung tissue structure is deformed, and honeycomb lung appears.

[0069] Pathological statistical results of the premature pig bronchopulmonary dysplasia model Figure 4 , Figure 4 Middle A shows that the radial alveolar count in the premature hyperoxia group was significantly lower than that in the premature control group and the full-term control group (P < 0.0001); Figure 4 Middle B shows that the Szapiel score of alveolitis in the premature hyperoxia group was significantly higher than that in the premature control group (P<0.01) and the full-term control group (P<0.05); Figure 4 Middle C shows that the collagen fiber area ratio in the premature hyperoxia group was significantly higher than that in the premature control group (P<0.01) and the full-term control group (<0.001); Figure 4 Middle D shows that the Ashcroft fibrosis score in the premature hyperoxia group was significantly higher than that in the premature control group and the full-term control group (P < 0.0001). Note: ns: no significant difference, *: P < 0.05, **: P < 0.01, ***: P < 0.001, ****: P < 0.0001.

[0070] From the above experiments, it can be determined that a neonatal bronchopulmonary dysplasia model can be prepared by using an inhaled oxygen concentration of 80-85%. Premature pigs inhale an oxygen concentration of 80-85%, breathe 30-50 times / minute, and begin to experience shortness of breath (breathing about 60-80 times / minute) at about 1 week. Shortness of breath begins to increase significantly (breathing about 80-120 times / minute) at about 2 weeks, accompanied by nasal cyanosis, difficulty feeding, and oxygen dependence. A chest X-ray is performed to determine lung changes in neonatal bronchopulmonary dysplasia, and then lung tissue pathology and other examinations are performed. This time point, i.e., the endpoint of the experiment, is 2-3 weeks after birth.

[0071] This application uses a pig model. Although pig models have been used as modeling animals for pulmonary respiratory distress syndrome before, the newborn pigs were not treated with high oxygen. Instead, it was a spontaneous model. The main problem with the spontaneous model is that some pigs will self-repair, resulting in modeling failure; and compared with small animals, pigs are closer to clinical human organ lesions.

[0072] The neonatal bronchopulmonary dysplasia model obtained in the present application is a non-invasive model. Compared with mechanical ventilation which requires invasive operations, the model is more operable to maintain high oxygen and is harmless to animals. Moreover, the construction method of the present application completely simulates clinical operations. In clinical practice, premature infants inhaling high oxygen lead to a high incidence of bronchopulmonary dysplasia, and the success rate of this modeling is relatively high. There was no such model construction operation in previous large animal models. In addition, the present application uses pigs delivered by caesarean section to simulate premature infants and uses inhalation of high-concentration oxygen to simulate clinical operations, with a high degree of clinical simulation.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application rather than to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present application.

Claims

1. A method for constructing a neonatal bronchopulmonary dysplasia model, characterized in that: The following steps are involved: S1. Select premature newborn pigs delivered by cesarean section and place them in an oxygen concentration of 70 ～ 85％ Raised in a breeding environment; S2. After 2 to 3 weeks of feeding, the respiratory system function indexes, lung tissue pathology indexes and imaging indexes of the newborn pigs were tested to obtain a neonatal bronchopulmonary dysplasia model.

2. The method for constructing a neonatal bronchopulmonary dysplasia model according to claim 1, characterized in that: In the step S1, the volume percentage concentration of oxygen is 80-85%.

3. The method for constructing a neonatal bronchopulmonary dysplasia model according to claim 1, characterized in that: In the step S1, the number of days of premature birth is 9 days.

4. The method for constructing a neonatal bronchopulmonary dysplasia model according to claim 1, characterized in that: In step S1, the breeding environment includes: a temperature of 33-35° C. and a humidity of 55%-60%.

5. The method for constructing a neonatal bronchopulmonary dysplasia model according to claim 1, characterized in that: In step S1, soda lime is placed in the breeding environment, and light / darkness is alternated every 12 hours.

6. The method for constructing a neonatal bronchopulmonary dysplasia model according to claim 1, characterized in that: In the step S1, an oxygen meter is used to monitor the oxygen volume percentage concentration in the breeding environment in real time, and the oxygen volume percentage concentration is maintained at 80-85%.

7. The method for constructing a neonatal bronchopulmonary dysplasia model according to claim 1, characterized in that: The newborn pigs were derived from Bama miniature pigs at 103 to 105 days of gestation.

8. The method for constructing a neonatal bronchopulmonary dysplasia model according to claim 1, characterized in that: In step S2, the newborn pigs show obvious shortness of breath, breathing at 80 to 120 times per minute, nasal cyanosis, dyspnea, oxygen dependence, and difficulty eating, and the lung tissue pathology and imaging indicators are detected.

9. The method for constructing a neonatal bronchopulmonary dysplasia model according to claim 1, characterized in that: In step S2, the lung tissue pathology indicators include radial alveolar counts, alveolitis scores, collagen area ratios and Ashcroft scores.

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