FUSED POLYPEPTIDE WITH MULTIFUNCTIONAL ACTIVITIES AND USE THEREOF

Abstract

The present disclosure discloses use of a fused polypeptide with multifunctional activities. In the fused polypeptide with multifunctional activities, the polypeptide contains the following domains: Pro-Arg-Cys-X-Y-Gly-Glu, where X is Trp or Tyr, and Y is Arg or Cys; and Gly-Gly-Gly-Gly-Ile-Val-Arg-Arg-Ala-Asp-Arg-Ala-Ala-Val-Pro-Gly-Gly-Gly-Gly-Arg-Gly-Asp; or a sequence of any amino acid mutated in the foregoing domains. The fused polypeptide can be used for treating various fibrosis diseases and symptoms, including pulmonary fibrosis, hepatic fibrosis, skin fibrosis, renal fibrosis, myocardial fibrosis, and lung tissue lesions.

Claims

1. A fused polypeptide with multifunctional activities, wherein the polypeptide comprises the following domains: TABLE-US-00016 Pro-Arg-Cys-X-Y-Gly-Glu, wherein X is Trp or Tyr,  and Y is Arg or Cys;  and Gly-Gly-Gly-Gly-lle-Val-Arg-Arg-Ala-Asp-Arg-Ala- Ala-Val-Pro-Gly-Gly-Gly-Gly-Arg-Gly-Asp, that is, Pro-Arg-Cys-X-Y-Gly-Glu-Gly-Gly-Gly-Gly-Ile-Val- Arg-Arg-Ala-Asp-Arg-Ala-Ala-Val-Pro-Gly-Gly-Gly- Gly-Arg-Gly-Asp, or a sequence of any amino acid mutated in the foregoing domains.

2. The fused polypeptide with multifunctional activities according to claim 1, wherein an amino acid sequence of the polypeptide is the following amino acid sequence or an amino acid sequence with 80% homology therewith: TABLE-US-00017 polypeptide I (SEQ ID NO: 1): Pro-Arg-Cys-Trp-Arg-Gly-Glu-Gly-Gly-Gly-Gly-Ile- Val-Arg-Arg-Ala-Asp-Arg-Ala-Ala-Val-Pro-Gly-Gly- Gly-Gly-Arg-Gly-Asp; polypeptide II (SEQ ID NO: 2): Pro-Arg-Cys-Tyr-Arg-Gly-Glu-Gly-Gly-Gly-Gly-Ile- Val-Arg-Arg-Ala-Asp-Arg-Ala-Ala-Val-Pro-Gly-Gly- Gly-Gly-Arg-Gly-Asp; polypeptide III (SEQ ID NO: 3): Pro-Arg-Cys-Trp-Cys-Gly-Glu-Gly-Gly-Gly-Gly-Ile- Val-Arg-Arg-Ala-Asp-Arg-Ala-Ala-Val-Pro-Gly-Gly- Gly-Gly-Arg-Gly-Asp;  and polypeptide IV (SEQ ID NO: 4): Pro-Arg-Cys-Tyr-Cys-Gly-Glu-Gly-Gly-Gly-Gly-Ile- Val-Arg-Arg-Ala-Asp-Arg-Ala-Ala-Val-Pro-Gly-Gly- Gly-Gly-Arg-Gly-Asp.

3. Use of the fused polypeptide with multifunctional activities according to claim 1 in the preparation of anti-fibrosis drugs.

4. Use of the fused polypeptide with multifunctional activities according to claim 1 in the preparation of drugs for resisting lung tissue lesions.

5. The use of the fused polypeptide with multifunctional activities in the preparation of anti-fibrosis drugs according to claim 3, wherein the tissue fibrosis comprises pulmonary fibrosis, hepatic fibrosis, renal fibrosis, myocardial fibrosis, and skin fibrosis.

6. The use of the fused polypeptide with multifunctional activities in the preparation of drugs for resisting lung tissue lesions according to claim 4, wherein the lung tissue lesions comprise bacterial pneumonia, viral pneumonia, mycoplasma pneumonia, fungal pneumonia, chlamydia pneumonia, and protozoal pneumonia.

7. The use of the fused polypeptide with multifunctional activities in the preparation of anti-fibrosis drugs according to claim 3, wherein the fused polypeptide is a polypeptide or a pharmaceutically acceptable salt thereof, and a dosage form of the polypeptide or the pharmaceutically acceptable salt thereof is an injection, a capsule, a tablet, a nasal spray or an aerosol.

8. The use of the fused polypeptide with multifunctional activities in the preparation of drugs for resisting lung tissue lesions according to claim 4, wherein the fused polypeptide is a polypeptide or a pharmaceutically acceptable salt thereof, and a dosage form of the polypeptide or the pharmaceutically acceptable salt thereof is an injection, a capsule, a tablet, a nasal spray or an aerosol.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0036] FIG. 1 is a diagram showing that polypeptides I, II, III and IV according to the present disclosure can lower the hydroxyproline content in a pulmonary fibrosis model;

[0037] FIG. 2 is a diagram showing that polypeptides I, I, III and IV according to the present disclosure can lower the TGF-β1 content in the pulmonary fibrosis model:

[0038] FIG. 3 is a diagram showing that polypeptides I, I, III and IV according to the present disclosure can lower the AST content in a hepatic fibrosis model:

[0039] FIG. 4 is a diagram showing that polypeptides I, II, III and IV according to the present disclosure can lower the ALT content in the hepatic fibrosis model;

[0040] FIG. 5 is a diagram showing that polypeptides I, I, III and IV according to the present disclosure can lower the hydroxyproline content in the hepatic fibrosis model;

[0041] FIG. 6 is a diagram showing that polypeptides I, II, III and IV according to the present disclosure can lower the TGF-β1 content in a renal fibrosis model;

[0042] FIG. 7 is a diagram showing that polypeptides I, II, III and IV according to the present disclosure can lower the TGF-β1 content in a myocardial fibrosis model;

[0043] FIG. 8 is a diagram showing that polypeptides I, I III and IV according to the present disclosure can lower the hydroxyproline content in a skin fibrosis model; and

[0044] FIG. 9 shows an inhibitory effect of polypeptides I, II, III and IV according to the present disclosure on pulmonary infections.

DESCRIPTION OF EMBODIMENTS

[0045] The polypeptide is synthesized by using a conventional solid phase synthesis method.

Embodiment 1 Pulmonary Fibrosis Animal Model

[0046] Experimental Animals and Materials:

1. Experimental Animals

[0047] Source and strain: clean SD rats, provided by Comparative Medicine Center of Yangzhou University (laboratory animal production license: SCXK (Su) 2012-0004); Certification of Using of Laboratory Animal: SYXK (Su) 2012-0035).

[0048] Weight: 180-200 g at the time of purchase, 190-210 g at the beginning of modeling, and 180-200 g at the beginning of administration.

[0049] Gender: Male.

2. Experimental Materials

[0050]

TABLE-US-00004 Bleomycin Manufacturer: Han Hui Pharmaceutical Co., Ltd. Normal saline Manufacturer: Anhui Double Crane Pharmaceutical Co., Ltd. Chloral hydrate Manufacturer: Sinopharm Chemical Reagent Co., Ltd. Rat TGF-β1 Manufacturer: Tianjin Annuo Ruikang ELISA kit Biotechnology Co., Ltd. Alkaline HYP kit Manufacturer: Nanjing Jiancheng Bioengineering Institute BIBF1120 Manufacturer: Jinan Synovel (nintedanib) Chemical Co., Ltd.

3. Experimental Method

[0051] SD rats were anesthetized by intraperitoneal injection of 1 mL/100 g 4% chloral hydrate. After anesthesia, the rats were fixed and their necks were disinfected by using cotton with 75% alcohol. The skin of the rat neck was longitudinally cut with scissors, and the fascia and muscle were longitudinally bluntly torn with tweezers to expose the trachea. A syringe was inserted into the trachea to inject 5 mg/kg bleomycin, while a blank group was injected with an equal amount of normal saline. Then a rat plate was quickly erected and rotated, the rats' breathing was observed, the neck wound was sterilized after rotation and was sewn, and an amoxicillin anti-inflammatory drug was sprinkled on the suture. After the operation, the rats were put back into a dry and clean cage for resting, waiting was performed for awakening. The rats were awakened after about 1-2 hours, and then fed normally. On the 7.sup.th day after modeling, modeling group animals randomly fell into a model group, a Nintedanib positive drug group, polypeptide I, II, III and IV dosage groups, and a normal control group, and the groups were administered separately for an administration cycle of 14 days. Living situations of rats were observed every day and their weights were weighed. After administration for 14 days, the eyeballs were removed and blood was taken, the rats were dissected, and lungs were taken. The content of TGF-β1 in serum and the content of HYP in lung tissues were detected.

4 Experimental Grouping and Dosage Setting

[0052]

TABLE-US-00005 TABLE 1 Experimental grouping and dosage regimen Administration Administration Group Drug Dosage mode frequency Quantity Blank group Normal saline 0.5 mL/200 g Subcutaneous Twice a day 14 injection Model group Normal saline 0.5 mL/200 g Subcutaneous Twice a day 14 injection Positive drug Nintedanib 25 mg/kg Intragastric Once a day 14 administration Test drug (1) Polypeptide I 10 mg/kg Subcutaneous Twice a day 14 injection Test drug (2) Polypeptide II 10 mg/kg Subcutaneous Twice a day 14 injection Test drug (3) Polypeptide III 10 mg/kg Subcutaneous Twice a day 14 injection Test drug (4) Polypeptide IV 10 mg/kg Subcutaneous Twice a day 14 injection

5. Experimental Results

[0053] (1) Impact of a Polypeptide on the Survival Rate of SD Rats Induced by Bleomycin

[0054] As shown in Table 2, compared with the survival rate (57.19%) of SD rats in the model group, the survival rate of SD rats in each test drug group was higher than that of the model group, each test drug could significantly increase the survival rate of SD rats, and the survival rate of the polypeptide I group and the survival rate of the polypeptide III group was equivalent to that of the positive drug group. The survival rate of polypeptide IV (92.9%) was higher than that of the positive drug group (85.7%)

TABLE-US-00006 TABLE 2 Impact of a polypeptide on survival rate (%) of SD rate with bleomycin-induced pulmonary fibrosis Number of Number of Dosage animals at animals at Survival Group (mg/kg) the beginning the end rate (%) Blank group — 14 14 100 Model group — 14 8 57.1 Positive drug group 10 14 12 85.7 Polypeptide I 10 14 12 85.7 Polypeptide II 10 14 11 78.6 Polypeptide III 10 14 12 85.7 Polypeptide IV 10 14 13 92.9

[0055] (2) Impact of a Polypeptide on the Content of TGF-β1 in Serum of SD Rats with Bleomycin-Induced Pulmonary Fibrosis

[0056] TGF-β1 is the most important fibrogenic factor. In pulmonary fibrosis, the expression content of TGF-β1 was significantly increased. The result is shown in FIG. 1, and there was a highly significant difference between the model group and the blank group (**P<0.001). After administration, all groups could significantly reduce the content of TGF-β1 in serum, the nintedanib positive drug group, the polypeptide I group, the polypeptide II group and the polypeptide III group were highly significantly different from the model group (***P<0.001), and the polypeptide IV group was highly significantly different from the model group (**P<0.01).

[0057] (3) Impact of a Polypeptide on the Content of HYP in SD Rat Lung Tissues with Bleomycin-Induced Pulmonary Fibrosis

[0058] Lung tissues of each group were taken to detect the content of hydroxyproline in the lung tissue. As the characteristic protein of collagen, hydroxyproline can reflect the content of collagen in the lung tissue from the side. As shown in FIG. 2, the content of HYP in the model group significantly increased, and compared with the blank group, the model group was extremely significantly different (***P<0.001). After administration, each group could significantly reduce the expression of HYP in lung tissues. Polypeptide I and polypeptide II could significantly reduce the expression content of HYP in lung tissues, and had better effects than the positive drug, and the polypeptide I group and the polypeptide II group were highly significantly different from the model group (***P<0.001). The positive drug group and the polypeptide IV group were highly significantly different from the model group (**P<0.01); and the polypeptide III group was significantly different from the model group (*P<0.05).

Embodiment 2 Hepatic Fibrosis Animal Model

1. Experimental Animals

[0059] Source and strain: SPF level. SD rats, provided by Shanghai Xipuer-Bikai laboratory Animal Co., Ltd. (laboratory animal license: SCXK (hu) 2013-0016)

[0060] Weight: 180-200 g at the time of purchase and 200-220 g at the beginning of modeling

[0061] Gender: Male.

2. Experimental Materials

[0062]

TABLE-US-00007 Carbon tetrachloride Manufacturer: Shanghai Aladdin Reagent Co., Ltd. Normal saline Manufacturer: Anhui Double Crane Pharmaceutical Co., Ltd. Olive oil Manufacturer: Sangon Biotech (Shanghai) Co., Ltd. Alkaline HYP kit Manufacturer: Nanjing Jiancheng Bioengineering Institute Glutamic-oxalacetic Manufacturer: Nanjing Jiancheng transaminease test kit Bioengineering Institute Glutamic-pyruvic Manufacturer: Nanjing Jiancheng transaminase test kit Bioengineering Institute

3. Experimental Method

[0063] Male SD rats fell into the following groups, and the groups were shown in the following table. There were 10 rats in each group. Modeling was performed on the rats. Each group other than the blank group was injected with 40% CCl.sub.4 intraperitoneally twice a week, the first injection was performed at 3 mL/kg, and then administration was performed at 2 mL/kg. Administration was performed for 8 weeks, and a total of 16 injections were provided to induce hepatic fibrosis. After the intraperitoneal injection of CCl.sub.4 for the fourth time, polypeptide therapy was started on the next day, and administration was performed by subcutaneous injection once a day until the end of induction. After the intraperitoneal injection of CCl.sub.4 for the fourth time, colchicine was administrated on the next day at 200 μg/kg, 5 times a week, and intragastric administration therapy was implemented. After induction for 8 weeks, the administration was stopped. On the second day, the SD rats were dissected, blood was taken, and the liver tissue was taken and stored in a refrigerator at −80° C. for later use. The expressions of AST and ALT in serum and HYP in the rat liver tissue were detected.

4. Experimental Grouping and Dosage Regimen

[0064]

TABLE-US-00008 TABLE 3 Experimental grouping and dosage regimen Administration Administration Group Drug Dosage mode frequency Quantity Blank group Normal saline 0.5 mL/200 g Subcutaneous Once a day 10 injection Model group Normal saline 0.5 mL/200 g Subcutaneous Once a day 10 injection Positive drug Colchicine 0.4 mg/kg Intragastic 5 times/week 10 administration Test drug (1) Polypeptide I 6 mg/kg Subcutaneous Once a day 10 injection Test drug (2) Polypeptide II 6 mg/kg Subcutaneous Once a day 10 injection Test drug (3) Polypeptide III 6 mg/kg Subcutaneous Once a day 10 injection Test drug (4) Polypeptide IV 6 mg/kg Subcutaneous Once a day 10 injection

5. Experimental Results

[0065] (1) Expressions of AST and ALT in Serum of Rats in Each Group

[0066] Long-term stimulation with CCl.sub.4 could cause liver cell necrosis, inflammation and fibrous tissue proliferation in rats, accompanied by the increase of serum aspartate transaminase (AST) and alanine aminotransferase (ALT), and infiltration of a large number of inflammatory cells and deposition of a large number of collagen in extracellular matrix occurred. The contents of AST and ALT in the serum of rats in the normal group, the colchicine group and each polypeptide group were significantly lower than those in the model group, the levels of ALT and AST in serum in the model group were significantly higher than those in the normal group, and the model group was highly significantly different from the normal group (***P<0.001). The content of AST in serum in the colchicine group could be lowered, and the colchicine group was highly significantly different from the model group (**P<0.01). Polypeptides I, II, III and IV could reduce the content of AST in serum, and the polypeptide I group, the polypeptide II group, the polypeptide III group and the polypeptide IV group were highly significantly different from the model group (***P<0.001). The results are shown in FIG. 3. Each administration group could remarkably lower the content of ALT in serum, and was highly significantly different from the model group (***P<0.001). The results are shown in FIG. 4.

[0067] (2) Content of HYP in the Liver Tissue of Rats in Each Group

[0068] Liver tissues of each group were taken to detect the content of hydroxyproline in the liver tissue. As the characteristic protein of collagen, hydroxyproline can reflect the content of collagen in the liver tissue from the side. As shown in FIG. 5, the content of HYP in the model group was significantly higher than that in the blank group. Polypeptides I, II, III and IV and colchicine, the positive drug, could significantly lower the expression of HYP in liver tissue, and each polypeptide group and the positive drug group were highly significantly different from the model group (***P<0.001).

Embodiment 3 Establishment of a Renal Fibrosis Model

1. Experimental Animals

[0069] Clean grade male SD rats, purchased from Nanjing Qinglong Mountain Animal Farm, and weighed 180-200 g at the time of purchase, 190-210 g at the beginning of modeling, and 180-200 g at the beginning of administration.

2. Experimental Materials

[0070]

TABLE-US-00009 Normal saline Manufacturer: Anhui Double Crane Pharmaceutical Co., Ltd. Rat TGF-β1 Manufacturer: Tianjin Annuo Ruikang ELISA kit Biotechnology Co., Ltd. Alkaline HYP kit Manufacturer: Nanjing Jiancheng Bioengineering Institute

3. Experimental Method

[0071] A renal fibrosis animal model was established. SD rats were anesthetized with 4% chloral hydrate, injected with 1 mL/100 g intraperitoneally, fixed to an operation board, and sterilized in an operation area for later use. The abdominal cavity was cut open about 3-4 mm to the left of the ventrimeson, left kidney ureter was separated in an operation group, the ureter was ligated and separated close to the ureter near the lower pole of the inferior pole of kidney, and the ureter was cut short between two ligations after the double ligations. Muscular layers and abdominal walls were sewed layer by layer, the suture was disinfected with alcohol. After SD rats woke up, the rats were put into a cage for feeding. In the blank group, ureter was not ligated, and other steps were the same.

[0072] Then, the animals fell into a blank group, a model group, and polypeptide administration groups, with 10 animals in each group, and the administration was started on the second day after the operation, and was performed for 14 days. After administration for 14 days, blood was taken and supernatant was taken to detect the content of TGF-β1 in serum.

4. Experimental Grouping and Dosage Setting

[0073]

TABLE-US-00010 TABLE 4 Experimental grouping and dosage regimen Administration Administration Group Drug Dosage mode frequency Quantity Blank group Normal saline 0.5 mL/200 g Subcutaneous Once a day 10 injection Model group Normal saline 0.5 mL/200 g Subcutaneous Once a day 10 injection Test drug (1) Polypeptide I 6 mg/kg Subcutaneous Twice a day 10 injection Test drug (2) Polypeptide II 6 mg/kg Subcutaneous Twice a day 10 injection Test drug (3) Polypeptide III 6 mg/kg Subcutaneous Twice a day 10 injection Test drug (4) Polypeptide IV 6 mg/kg Subcutaneous Twice a day 10 injection

5. Experimental Results

[0074] (1) Impact of a Polypeptide on the Content of TGF-β1 in Serum of SD Rats with Renal Fibrosis

[0075] TGF-β1 is the most important fibrogenic factor. In renal fibrosis, the expression of TGF-β1 was significantly increased. The result is shown in FIG. 6, and there was a highly significant difference between the model group and the blank group (***P<0.001). After administration, each group could significantly reduce the content of TGF-β1 in serum, and the polypeptide I group, the polypeptide II group and the polypeptide IV group were highly significantly different from the model group (***P<0.001), and the polypeptide III group was highly significantly different from the model group (**P<0.01).

Embodiment 4 Establishment of a Myocardial Fibrosis Model

1. Experimental Mice: 10-Week-Old Male BALB/c Mice (with an Average Weight of 20 g)

2. Experimental Materials

[0076]

TABLE-US-00011 Normal saline Manufacturer: Anhui Double Crane Pharmaceutical Co., Ltd. Rat TGF-β1 Manufacturer: Tianjin Ammo Riukang ELISA kit Biotechnology Co., Ltd. Isoprenaline (ISO) Manufacturer: Sigma

3. Experimental Method

[0077] In the model group, the experimental mice were injected with isoprenaline (ISO) (5 mg/kg) subcutaneously on the back of the mice every day for 7 consecutive days, and the mice were injected with normal saline subcutaneously (200 μL/mouse) every day. In the blank group, normal saline was injected subcutaneously (200 μL/mouse) every day. While a model was made, polypeptide drugs were administrated for treatment by subcutaneous injection. After the 8.sup.th day, blood was taken and was centrifuged, the supernatant was taken, and the content of TGF-β1 in serum was detected.

4. Experimental Grouping and Dosage Setting

[0078]

TABLE-US-00012 TABLE 5 Experimental grouping and dosage regimen Administration Administration Group Drug Dosage mode frequency Quantity Blank group Normal saline 0.2 mL Subcutaneous Once a day 10 injection Model group Normal saline 0.2 mL Subcutaneous Once a day 10 injection Test drug (1) Polypeptide I 12 mg/kg Subcutaneous Twice a day 10 injection Test drug (2) Polypeptide II 12 mg/kg Subcutaneous Twice a day 10 injection Test drug (3) Polypeptide III 12 mg/kg Subcutaneous Twice a day 10 injection Test drug (4) Polypeptide IV 12 mg/kg Subcutaneous Twice a day 10 injection

5. Experimental Results

[0079] (1) Impact of a Polypeptide on the Content of TGF-β1 in Serum of Mice with Myocardial Fibrosis

[0080] TGF-β1 is the most important fibrogenic factor. In myocardial fibrosis, the expression of TGF-β1 was significantly increased. The result is shown in FIG. 7, and there was a highly significant difference between the model group and the blank group (***P<0.001). After administration, each group could significantly reduce the content of TGF-β1 in serum, and the polypeptide I group and the polypeptide III group were highly significantly different from the model group (**P<0.01), and the polypeptide II group and the polypeptide IV group where highly significantly different from the model group (*P<0.05).

Embodiment 5 Establishment of a Skin Fibrosis Model

1. Experimental Animals

[0081] Male C57/BL black mice aged 6-8 weeks, purchased from Nanjing Qinglong Mountain Animal Farm.

2. Experimental Materials

[0082]

TABLE-US-00013 Bleomycin Manufacturer: Han Hui Pharmaceutical Co., Ltd. Normal saline Manufacturer: Anhui Double Crane Pharmaceutical Co., Ltd. Rat TGF-β1 Manufacturer: Tianjin Annuo Ruikang ELISA kit Biotechnology Co., Ltd. Alkaline HYP kit Manufacturer: Nanjing Jiancheng Bioengineering Institute

3. Modeling Method

[0083] Bleomycin (10 μg/mL) was injected subcutaneously every day for 28 days to form skin fibrosis. During the modeling period, the administration groups were given polypeptide drugs twice a day for treatment. After modeling, the mice were killed on the next day, and the skin tissue of the mouse back was taken to detect the content of HYP in the skin tissue.

4. Experimental Grouping and Dosage Regimen

[0084]

TABLE-US-00014 TABLE 6 Experimental grouping and dosage regimen Administration Administration Group Drug Dosage mode frequency Blank group Normal saline 0.2 mL Subcutaneous Twice a day injection Model group Normal saline 0.2 mL Subcutaneous Twice a day injection Test drug (1) Polypeptide I 10 mg/kg Subcutaneous Twice a day injection Test drug (2) Polypeptide II 10 mg/kg Subcutaneous Twice a day injection Test drug (3) Polypeptide III 10 mg/kg Subcutaneous Twice a day injection Test drug (4) Polypeptide IV 10 mg/kg Subcutaneous Twice a day injection

5. Experimental Results

[0085] (1) Expression of HYP Content in the Skin Tissue of Each Group of Mice

[0086] The content of hydroxyproline in the skin tissue of the mouse back was detected. As the characteristic protein of collagen, hydroxyproline can reflect the content of collagen in the skin tissue from the side. As shown in FIG. 8, each polypeptide group could reduce the expression of HYP in the skin tissue. Polypeptide I could significantly reduce the expression of HYP in the skin tissue, and the polypeptide I group was highly significantly different from the model group (**P<0.01). The polypeptide II group, the polypeptide III group and the polypeptide IV group could reduce the content of HYP in the skin tissue of mice, and were highly significantly different from the model group (*P<0.05).

Embodiment 6 Inhibitory Effect of a Polypeptide According to the Present Disclosure on Multiple Pulmonary Infections

[0087] A mouse pneumonia model was successfully established by using a nasal drip method. BALB/C mice with a body weight of 18-24 g were selected, and then anesthetized with ether on day 0, day 1 and day 2, respectively, prepared Streptococcus pneumoniae bacteria solution, adenovirus concentrated solution, Mycoplasma pneumoniae, Chlamydia pneumoniae, protozoa and pneumonia fungi were slowly dropped into the nasal cavity of the mice, so that the bacteria solutions entered the trachea and bronchi, and the bacteria solutions were prevented from flowing into the esophagus during the operation to avoid inactivation of the bacteria solutions, so that the mouse pneumonia model was established. After the model was successfully established, the polypeptide according to the present disclosure was administered, as shown in FIG. 9 and Table 7. The results show that compared with the drug in the penicillin administration group, the polypeptide according to the present disclosure had a more significant improvement effect on a plurality of lung infections. The experimental results are represented on the basis of average values±standard deviation.

TABLE-US-00015 TABLE 7 Inhibitory effect of a polypeptide according to the present disclosure on multiple pulmonary infections Pneumonia type Polypeptide I Polypeptide II Polypeptide III Polypeptide IV Penicillin Bacterial 34.83 ± 7.95 41.25 ± 9.48 47.29 ± 8.76 43.69 ± 8.66 37.05 ± 4.35 pneumonia Viral 50.00 ± 6.84 50.27 ± 8.08 67.49 ± 9.94 70.33 ± 9.27 48.07 ± 2.07 pneumonia Mycoplasma 36.48 ± 5.55 45.69 ± 5.72 43.93 ± 5.53 41.20 ± 7.30 39.78 ± 5.23 pneumonia Chlamydia 37.18 ± 7.46 45.81 ± 5.21 56.40 ± 5.49 45.86 ± 5.22 32.57 ± 3.13 pneumonia Protozoal 48.16 ± 5.46 63.60 ± 6.16 64.29 ± 8.70 62.16 ± 3.28 40.34 ± 3.02 pneumonia Fungal 47.54 ± 9.68 60.32 ± 3.07 62.88 ± 5.94 53.22 ± 4.14 36.87 ± 2.82 pneumonia Pneumonia 47.52 ± 7.88 63.15 ± 5.87 56.81 ± 3.13 50.99 ± 6.88 39.56 ± 4.35 caused by pulmonary infections