Construction method and application of bronchiectasis animal model

Abstract

The invention belongs to the technical field of animal model construction, and particularly relates to a construction method and application of a bronchiectasis animal model. According to the method, the bronchiectasis animal model is constructed in a manner of alternately infecting the animal with the self-separated pseudomonas aeruginosa and injecting the protease into the airway of the animal, so that the stable bronchiectasis animal model is successfully obtained, and the modeling success rate is relatively high. It is confirmed through imaging and pathological detection means that the constructed bronchiectasia animal model meets the diagnostic standard of bronchiectasia, chronic pseudomonas aeruginosa airway infection in bronchiectasia can be accurately simulated, structural changes of bronchiectasia are copied, and auxiliary clinical research and application are facilitated.

Description

Technical Field

[0001] This invention belongs to the field of animal model construction technology, specifically relating to a method for constructing an animal model of bronchiectasis and its application. Background Art

[0002] Bronchiectasis (BDE) is a chronic inflammatory and infectious disease of the airways, characterized by chronic cough, recurrent infections, and respiratory tract damage and remodeling. It has a high prevalence and mortality rate worldwide. Patients often present with persistent cough, purulent sputum, recurrent chest discomfort, and lethargy. Due to the heavy medical burden and rising average hospitalization costs associated with the high prevalence of BDE, it has gradually gained attention and focus from patients, medical staff, and researchers.

[0003] Animal models of bronchiectasis are core tools in exploring the pathogenesis of bronchiectasis and in the development of new drugs. However, there is currently no specific modeling method for bronchiectasis, resulting in a lack of suitable disease models in this field. The current mainstream alternative model is the chronic Pseudomonas aeruginosa infection model, but this model has significant limitations: the infection is easily controlled quickly and it is difficult to establish a chronic state; excessively high doses can easily cause acute systemic infection and death in animals; and it is not a bronchiectasis-specific model in nature. In summary, a reliable animal model for bronchiectasis is still lacking in this field. Summary of the Invention

[0004] The purpose of this invention is to provide a method for constructing an animal model of bronchiectasis and its application. The method can successfully construct a stable animal model of bronchiectasis with a high success rate.

[0005] This invention provides a method for constructing an animal model of bronchiectasis, comprising the following steps:

[0006] 1) Infecting animals with Pseudomonas aeruginosa;

[0007] 2) After 6-8 days, inject the protease into the airway of the animal obtained in step 1);

[0008] 3) After 6-8 days, infect the animals obtained in step 2) with Pseudomonas aeruginosa;

[0009] 4) After 6 to 8 days, the protease is injected into the airway of the animal obtained in step 3) to obtain the bronchiectasis animal model.

[0010] Preferably, the Pseudomonas aeruginosa includes Pseudomonas aeruginosa FKC2, and the preservation number of Pseudomonas aeruginosa FKC2 is GDMCC No. 64358.

[0011] Preferably, the protease includes papain.

[0012] Preferably, the method for infecting animals with Pseudomonas aeruginosa includes injecting Pseudomonas aeruginosa agar beads into the animal's airway; the diameter of the Pseudomonas aeruginosa agar beads is 100-200 μm.

[0013] Preferably, the single infection dose of the *Pseudomonas aeruginosa* is 3 × 10⁻⁶. 6 CFU / each.

[0014] Preferably, the single injection dose of the protease is 20 μL / animal, and the concentration of the protease is 1.25 mg / mL.

[0015] Preferably, the construction method further includes evaluating whether the bronchiectasis animal model has been successfully constructed using imaging and / or pathological testing methods.

[0016] Preferably, the imaging examination method includes CT, and the pathological examination method includes HE staining.

[0017] This invention also provides the application of the construction method described in the above technical solution or the bronchiectasis animal model constructed by the construction method described in the above technical solution in any of the following two situations:

[0018] 1) To prepare products for the prevention and / or treatment of bronchiectasis;

[0019] 2) Drug screening.

[0020] The present invention also provides a Pseudomonas aeruginosa FKC2, the preservation number of which is GDMCC No. 64358.

[0021] Beneficial effects:

[0022] This invention provides a method for constructing an animal model of bronchiectasis, comprising the following steps: 1) infecting animals with *Pseudomonas aeruginosa*; 2) injecting a protease into the airway of the animal obtained in step 1) after 6-8 days; 3) infecting the animal obtained in step 2) with *Pseudomonas aeruginosa* after 6-8 days; 4) injecting a protease into the airway of the animal obtained in step 3) after 6-8 days, thereby obtaining the bronchiectasis animal model. This invention constructs a bronchiectasis animal model by alternating between infecting animals with self-isolated *Pseudomonas aeruginosa* and injecting protease into the animal's airway, successfully obtaining a stable bronchiectasis animal model with a high success rate. Imaging and pathological examinations confirmed that the constructed bronchiectasis animal model meets the diagnostic criteria for bronchiectasis, accurately simulates chronic *Pseudomonas aeruginosa* airway infection in bronchiectasis, and replicates the structural changes of bronchiectasis, facilitating clinical research and application.

[0023] Biological Preservation Information

[0024] Pseudomonas aeruginosa FKC2 was deposited on February 1, 2024, at the Guangdong Provincial Microbial Culture Collection Center (GDMCC), with accession number GDMCCNo. 64358. The depository address is: 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou, Guangdong Academy of Sciences, Postcode 510070. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0026] Figure 1 This is a flowchart illustrating the construction process of the bronchiectasis mouse model in Example 1;

[0027] Figure 2 This is a typical bronchiectasis-like phenotype induced in the bronchiectasis mouse model of Example 1;

[0028] Figure 3 The CT scan of the bronchiectasis-like phenotype in the mouse model of Example 1 shows typical bronchiectasis-like features.

[0029] Figure 4 HE staining results of lung tissue sections from the bronchiectasis mouse model in Example 1. Detailed Implementation

[0030] This invention provides a method for constructing an animal model of bronchiectasis, comprising the following steps:

[0031] 1) Infecting animals with Pseudomonas aeruginosa;

[0032] 2) After 6-8 days, inject the protease into the airway of the animal obtained in step 1);

[0033] 3) After 6-8 days, infect the animals obtained in step 2) with Pseudomonas aeruginosa;

[0034] 4) After 6 to 8 days, the protease is injected into the airway of the animal obtained in step 3) to obtain the bronchiectasis animal model.

[0035] This invention involves infecting animals with Pseudomonas aeruginosa.

[0036] In one embodiment, the animal described in this invention is a mouse. In another embodiment, the *Pseudomonas aeruginosa* described in this invention is *Pseudomonas aeruginosa* FKC2, whose preservation number is GDMCC No. 64358. The *Pseudomonas aeruginosa* FKC2 described in this invention is a self-isolated chronic *Pseudomonas aeruginosa* strain. Using this strain combined with papain to construct a bronchiectasis animal model, compared with existing models using the PAO1 strain with repeated infections but lacking CT imaging evidence of bronchiectasis, this model is the first to directly and clearly confirm the occurrence of bronchiectasis through CT imaging, exhibiting significant advantages such as high modeling efficiency, stable structural lesions, and high similarity to clinical imaging. In one embodiment, the method of infecting animals with *Pseudomonas aeruginosa* includes injecting *Pseudomonas aeruginosa* agar beads into the animal's airway. In one embodiment, the diameter of the *Pseudomonas aeruginosa* agar beads is 100–200 μm; in another embodiment, the diameter of the *Pseudomonas aeruginosa* agar beads is any value between 100 μm, 120 μm, 150 μm, 170 μm, 190 μm, 200 μm, or 100–200 μm. The present invention does not impose any particular limitation on the preparation process of the *Pseudomonas aeruginosa* agar beads; conventional methods in the art can be used to coat the *Pseudomonas aeruginosa* agar beads with agar. In one embodiment, the single infection dose of *Pseudomonas aeruginosa* according to the present invention is 3 × 10⁻⁶. 6 CFU / each.

[0037] Following infection of animals with *Pseudomonas aeruginosa*, the present invention injects a protease into the airway of the resulting animals 6-8 days later. In one embodiment, the protease is injected into the airway of the resulting animals 7 days later. In one embodiment, the protease is papain; in another embodiment, the papain activity is ≥2000 U / mg. In one embodiment, the single injection dose of the protease is 20 μL / animal; in another embodiment, the concentration of the protease is 1.25 mg / mL. Existing chronic experimental models have the following limitations: 1) Chronic bacterial airway infection models are infected too quickly, failing to establish a chronic state, and excessively high infection doses can easily lead to acute death in animals; 2) Coated strain models have a short duration, inconsistent with the clinical chronic course, and cannot induce bronchiectasis structural lesions. The present invention combines a protease to construct a novel mouse model that can promote airway epithelial damage and lung tissue structural destruction, maintain chronic infection stably for a long time, and accurately induce bronchiectasis structural changes. It has the advantages of stable model formation, high consistency with clinical characteristics, and high survival rate of experimental animals.

[0038] After injecting the protease into the animal's airway, the animal is reinfected with *Pseudomonas aeruginosa* 6-8 days later. In one embodiment, the animal is reinfected with *Pseudomonas aeruginosa* 7 days later. The relevant characteristics of *Pseudomonas aeruginosa* infection in the animal described in this invention are the same as in the above-described technical solutions and will not be repeated.

[0039] After reinfecting animals with *Pseudomonas aeruginosa*, the protease is injected back into the resulting animal airway 6-8 days later. In one embodiment, the protease is injected back into the resulting animal airway 7 days later. The relevant characteristics of injecting the protease into the animal airway in this invention are the same as in the above-described technical solutions and will not be repeated.

[0040] After the protease is reinjected into the animal airway, the construction method of the present invention further includes evaluating whether the bronchiectasis animal model has been successfully constructed using imaging and / or pathological detection methods. As one embodiment, the imaging detection method is CT; as another embodiment, the CT is high-resolution CT. As one embodiment, the standard for evaluating whether the bronchiectasis model has been successfully constructed using the imaging detection method of the present invention can be the diagnostic criteria for adult bronchiectasis. Meeting at least one of the following criteria is sufficient to diagnose a successful bronchiectasis model: ① internal airway diameter to artery diameter ratio ≥1.0; ② external airway diameter to artery diameter ratio ≥1.0; ③ no signs of gradual narrowing of the airway; ④ airway visible in the peripheral lung fields. As one embodiment, the pathological detection method can be HE staining.

[0041] This invention also provides the application of the construction method described in the above technical solution or the bronchiectasis animal model constructed by the construction method described in the above technical solution in either of the following two: 1) preparing products for the prevention and / or treatment of bronchiectasis; 2) drug screening. As one embodiment, the drug described in this invention is a drug for the prevention and / or treatment of bronchiectasis.

[0042] The present invention also provides a Pseudomonas aeruginosa FKC2, the preservation number of which is GDMCC No. 64358.

[0043] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0044] Example 1

[0045] A method for constructing an animal model of bronchiectasis, the flowchart of which is shown below. Figure 1 As shown, the steps are as follows:

[0046] 1. Experimental Materials

[0047] The experimental strain was Pseudomonas aeruginosa FKC2, with accession number GDMCC No. 64358 (hereinafter referred to as C2), which was isolated from the airway of a bronchiectasis patient in the inpatient department of Shanghai Pulmonary Hospital.

[0048] The protease was papain, purchased from Shanghai Sangon Biotech Co., Ltd., product number A501612-0025, with an enzyme activity ≥2000U / mg.

[0049] The model mice were 6-week-old female C57BL / 6 mice, weighing 16–18g.

[0050] 2. Experimental Methods

[0051] 2.1 Preparation of Pseudomonas aeruginosa agar beads (hereinafter referred to as "C2beads")

[0052] a) Initial shaking of bacteria: One day in advance, pick a single C2 colony from solid LB medium with an inoculation loop and inoculate it into a shaking tube containing 4 mL of LB liquid medium in a clean bench; then place the shaking tube in a shaker at 37°C and incubate at 220 rpm for 17 h.

[0053] b) Re-culture of bacteria: On the second day, use a pipette to take 500 μL of the bacterial culture obtained in step a) and add it to a 50 mL centrifuge tube containing LB liquid medium, and dilute it 1:20 to obtain the reculture system.

[0054] Prepare two identical reculture systems. Place the diluted bacterial solution in a shaker at 37°C and continue culturing for 4-5 hours to allow the bacteria to grow to the logarithmic growth phase.

[0055] c) Collection and resuspension of bacteria: The bacterial culture from step b) was placed at 4°C and centrifuged at 2700g for 3 min. The precipitate was then resuspended in 1 mL of bacterial culture and thoroughly mixed by shaking.

[0056] d) Preparation of agar beads: Add 9 mL of LB solid medium preheated to 50°C to the resuspended bacterial solution in step c), and vortex to mix thoroughly. Then add 10 mL of the above medium containing strain C2 to 150 mL of paraffin oil preheated to 50°C, and immediately place on a stirrer and stir for 6 min, during which visible vortices should be formed;

[0057] e) Cooling of agar beads: Transfer the stirred mixture along with the stirrer to a 4°C freezer and stir at low speed for 35 min. Then transfer the mixture to ice and incubate for 20 min;

[0058] f) Separation and purification of agar beads: Transfer the mixture from step e) to a 50 mL centrifuge tube and centrifuge at 2700 g for 3 min at 4 °C. At this point, mineral oil will be visible on the upper layer and agar beads on the lower layer. Carefully remove the upper layer of mineral oil, add PBS to a final volume of 50 mL, gently mix the agar beads, and centrifuge again at 2700 g for 3 min. Remove approximately 10 mL of the oily PBS from the upper layer, gently mix, and then transfer the solution containing small agar particles from the upper layer to a new 50 mL centrifuge tube, discarding the portion containing larger agar particles.

[0059] g) Filtration of agar beads: The solution obtained in step f) is filtered sequentially through filters with pore sizes of 200 μm and 100 μm to obtain agar beads with a diameter of 100–200 μm. Finally, sterile PBS solution is added to bring the volume to approximately 5–15 mL.

[0060] h) Agar bead disruption: After mixing the agar beads, use a pipette to take 0.5 mL of the mixed agar beads and place them in a sterile homogenizer for disruption.

[0061] i) Gradual dilution and counting of bacteria: The perforated agar-coated Pseudomonas aeruginosa was serially diluted 10-fold with sterile PBS solution. After thoroughly mixing the diluted Pseudomonas aeruginosa agar suspension on a shaker, 10 μL was spread onto the surface of a solid LB agar plate. After the liquid air-dried, the plate was placed in a 37°C incubator. The next day, the colonies formed on the culture medium were counted and the results were recorded.

[0062] j) Microscopic observation and preservation of agar beads: On day 1, take an appropriate amount of well-mixed *Pseudomonas aeruginosa* agar beads and add them to an empty plate containing PBS. Observe different fields of view under a microscope, take pictures and measure the diameter of the gel agar beads, and select agar beads with a diameter in the range of 100-200 μm. Store the intact *Pseudomonas aeruginosa* agar beads in a refrigerator at 4°C.

[0063] k) Determination of bacterial load: On day 2, the bacterial load of *Pseudomonas aeruginosa* on agar beads was counted. LB plates coated with agar gel microparticle homogenate were removed from the 37°C incubator, and colony forming units (CFU) at different dilutions were manually calculated. Based on the dilution concentration, the number of *Pseudomonas aeruginosa* bacteria embedded per milliliter of agar beads (CFU / mL) was calculated using the following formula: *Pseudomonas aeruginosa* agar bead bacterial load CFU / mL = (CFU at a certain dilution concentration / 0.1 mL) × dilution factor.

[0064] l) Dilution and preparation of agar beads: Based on the calculated bacterial load, add an appropriate amount of PBS to dilute the agar gel microparticles to the required concentration and prepare them for use.

[0065] 2.2 Infection of mice to establish a mouse model

[0066] 2.2.1 Mouse grouping

[0067] Mice were randomly divided into two groups of 5–8 healthy mice each, designated as the bronchiectasis group and the control group.

[0068] 2.2.2. Infusion treatment of bronchiectasis group mice

[0069] 2.2.2.1 On day 0 of modeling, C2 beads were instilled into the airways of mice.

[0070] a) After standardizing the bacterial count of the C2beads prepared in step 2.1, inject each mouse with 3 × 10⁻⁶ C2 strains. 6 CFU;

[0071] b) Attach the insulin needle to the sterile plastic tubing, with the end of the tubing extending approximately 5mm beyond the needle.

[0072] c) Place the anesthetized mouse in a supine position on the inclined operating table, with the mouse's incisors hanging on a horizontal rubber band and its limbs fixed with tape.

[0073] d) Turn on the cold light source, point the light source at the airway of the mouse, and carefully pull out the mouse's tongue with sterile curved forceps and place it on the left side;

[0074] e) The mouse glottis can be clearly seen under cold light. Gently insert the insulin needle tubing into the glottis and slowly inject C2 beads.

[0075] f) After observing that the mouse has obvious coughing, continue to hang the mouse with its head up for about 10 minutes to prevent the bacterial liquid from flowing back into the mouth;

[0076] g) Then, put the mouse back into its corresponding cage, mark it, and keep it warm. The mouse should wake up in about half an hour.

[0077] 2.2.2.2 On day 7 of modeling, papain was administered via infusion into the airways of mice.

[0078] Papain was administered into the airways of mice using the method described in step 2.2.2, which involved replacing the C2 beads in step e) with 20 μL of Papain (at a concentration of 1.25 mg / mL).

[0079] 2.2.2.3. On day 14 of modeling, C2 beads were instilled into the airways of mice.

[0080] The method is the same as step 2.2.2.1.

[0081] 2.2.2.4. On day 21 of modeling, Papain was administered via infusion into the airways of mice.

[0082] The method is the same as step 2.2.2.2.

[0083] 2.2.3 Control group mice received intravenous infusion treatment

[0084] The treatment method used in step 2.2.2 for the bronchiectasis group mice was adopted, except that the treatment of instilling C2 beads into the airway of mice and the treatment of instilling Papain into the airway of mice were both replaced with the same volume of PBS.

[0085] 2.3 Evaluation of Modeling Results

[0086] On day 28 of modeling, mice underwent high-resolution CT (HRCT) examination of the chest, with parameters set to 90kV, 88mA, and high resolution.

[0087] Small animal lung CT imaging was used to verify whether the model possessed the typical imaging features of bronchiectasis. The imaging evaluation criteria were based on the adult diagnostic criteria for bronchiectasis, mainly including the following characteristics: ① the ratio of internal airway diameter to artery diameter ≥1.0; ② the ratio of external airway diameter to artery diameter ≥1.0; ③ no signs of gradual narrowing of the airway; ④ airways visible in the peripheral lung fields. Meeting any one of the above criteria is sufficient for a diagnosis of bronchiectasis.

[0088] High-resolution CT scan results of the chest, as shown Figure 2 As shown. In Figure 2 In the images, A to C are representative CT images of the lungs of healthy control mice; D shows typical signet ring sign in the bronchiectasis group mice, with axial CT images (left) and schematic diagrams (right) showing dilated trachea and accompanying blood vessels. The blue circles indicate the inner diameter of the dilated trachea, and the red images show the accompanying blood vessels; E is an enlarged view of image F, with radiological findings including columnar dilation of the trachea and mucus accumulation; F shows that tracheal dilation in the bronchiectasis group mice mainly occurs in the area surrounding the lungs.

[0089] from Figure 2 From A to C, it can be concluded that the lung CT images of the healthy control group mice were clear and did not show the characteristic changes of bronchiectasis mentioned above. However, in the bronchiectasis group, the typical bronchiectasis lesion features were very obvious, such as... Figure 2 As shown in D, signet ring syndrome is present in the lungs. E shows columnar dilatation in the model mice, with mucus accumulation in the trachea; F shows peripheral tracheal dilatation.

[0090] The ratio of bronchial diameter to accompanying pulmonary artery diameter is a key imaging indicator for the diagnosis of bronchiectasis. This invention involved detailed measurements in mice with bronchiectasis, and the results are as follows: Figure 3 As shown, in Figure 3In the images, A to C represent typical signet ring signs in the bronchiectasis group mice; D to F show CT images showing that the airways did not gradually narrow; and G to I show CT images showing dilated airways in the peripheral lung fields.

[0091] The bronchiectasis group clearly exhibited typical bronchiectasis-like radiographic features. First, Figure 3 In group A, the trachea / accompanying vessel diameter ratio was 0.42 mm / 0.23 mm; in group B, it was 0.38 mm / 0.24 mm; and in group C, it was 0.39 mm / 0.22 mm. All ratios were significantly greater than 1, which is highly consistent with the diagnostic criteria for bronchiectasis and clearly indicates the lesion site of the abnormal airway / artery diameter ratio. Furthermore, all mice exhibited typical signet ring sign, a characteristic imaging finding that further enhances the reliability of the bronchiectasis diagnosis. Secondly, in the bronchiectasis group, columnar dilation of the airway was clearly observed. Figure 2 E, Figure 3 (D-F) This lesion is characterized by the absence of the normal, gradually narrowing physiological characteristic of the distal airways. Normally, the airways gradually narrow as they branch to maintain efficient gas exchange, but this normal morphological change disappears in bronchiectasis, indicating that the lesions are mainly concentrated in the distal airways. Furthermore, CT images clearly show dilated airways in the peripheral regions of the lungs, a highly characteristic feature of bronchiectasis. Figure 2 China F, Figure 3 Medium G~I).

[0092] In summary, these three unique imaging features—abnormal airway-to-accompanying-vessel diameter ratio, columnar airway dilation, and bronchial dilation in the peripheral lung region—provide strong imaging evidence for the diagnosis of bronchiectasis by CT scan of the lungs.

[0093] Furthermore, the largest section of the lung was taken for pathological examination and stained with hematoxylin and eosin (HE) to observe whether the model was successfully established. The results are as follows: Figure 4 As shown. In Figure 4 In the table, A represents the HE staining results of lung tissue sections from control group mice, with a scale bar length of 2.5 mm; B represents the HE staining results of lung tissue sections from control group mice, with a scale bar length of 200 μm; C and E represent the HE staining results of lung tissue sections from bronchiectasis group mice, with a scale bar length of 2.5 mm; D and F represent the HE staining results of lung tissue sections from bronchiectasis group mice, with a scale bar length of 200 μm.

[0094] HE image analysis revealed that the lung tissue structure of the control group healthy mice was normal, with no obvious inflammatory cell infiltration. Figure 4 The middle group (A-B) showed mild pneumonia, while the bronchiectasis group exhibited mild pneumonia, with the inflammatory area mainly distributed around the airways. Figure 4The bronchiectasis pattern (D-F) differs from the extensive lung damage observed in acute infections and severe lung injuries. Furthermore, histopathological examination revealed that the trachea was primarily surrounded by lymphocytes, neutrophils, and monocytes, indicating an active immune response around the airways and a tendency for chronic inflammatory changes. Simultaneously, significant perivascular infiltration of inflammatory cells was observed, with lesions mainly concentrated around the lung airways. This series of histological findings corroborates the aforementioned imaging features, revealing the pathological characteristics of the bronchiectasis model at different levels.

[0095] To evaluate the success rate of the bronchiectasis mouse model, the present invention conducted three replicate experiments using the modeling method described in Example 1, with 5–10 mice used each time. The results showed that over 80% of the mice exhibited typical bronchiectasis characteristics, indicating that the model has high reproducibility and stability.

[0096] From the above embodiments, it can be concluded that the animal model construction method described in this invention can successfully construct a stable bronchiectasis animal model that meets the diagnostic criteria for bronchiectasis, and its success rate is also relatively high.

[0097] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for constructing an animal model of bronchiectasis, characterized in that, Includes the following steps: 1) Infecting animals with Pseudomonas aeruginosa; 2) After 6-8 days, inject the protease into the airway of the animal obtained in step 1); 3) After 6-8 days, infect the animals obtained in step 2) with Pseudomonas aeruginosa; 4) After 6 to 8 days, the protease is injected into the airway of the animal obtained in step 3) to obtain the bronchiectasis animal model.

2. The construction method according to claim 1, characterized in that, The *Pseudomonas aeruginosa* includes *Pseudomonas aeruginosa* FKC2, whose preservation number is GDMCC No. 64358.

3. The construction method according to claim 1, characterized in that, The protease includes papain.

4. The construction method according to claim 1 or 2, characterized in that, The method for infecting animals with Pseudomonas aeruginosa includes injecting Pseudomonas aeruginosa agar beads into the animal's airway; the diameter of the Pseudomonas aeruginosa agar beads is 100-200 μm.

5. The construction method according to claim 4, characterized in that, The single infection dose of the *Pseudomonas aeruginosa* was 3 × 10⁻⁶. 6 CFU / each.

6. The construction method according to claim 1 or 3, characterized in that, The single injection dose of the protease is 20 μL / animal, and the concentration of the protease is 1.25 mg / mL.

7. The construction method according to claim 1, characterized in that, The construction method also includes evaluating whether the bronchiectasis animal model has been successfully constructed using imaging and / or pathological testing methods.

8. The construction method according to claim 7, characterized in that, The imaging methods include CT, and the pathological methods include HE staining.

9. The use of the bronchiectasis animal model constructed by the construction method according to any one of claims 1 to 8, or by the construction method according to any one of claims 1 to 8, in any two of the following: 1) To prepare products for the prevention and / or treatment of bronchiectasis; 2) Drug screening.

10. A strain of Pseudomonas aeruginosa, FKC2, wherein the preservation number of Pseudomonas aeruginosa FKC2 is GDMCC No. 64358.

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