Use of lactobacillus casei gkc1 for the preparation of oral compositions for reducing the endotoxin content in serum

Abstract

The present application relates to the use of Lactobacillus casei GKC1 for preparing an oral composition for reducing the endotoxin content in serum. After the administration of Lactobacillus casei GKC1 to a subject with respiratory allergy, the respiratory resistance of the subject is improved, and the content of immunoglobulin E specific to allergen and the content of endotoxin in the serum of the subject are reduced, so that Lactobacillus casei GKC1 can be used as an effective component of an oral composition for reducing the endotoxin content in serum.

Description

[Technical Field]

[0001] This invention relates to the use of an oral composition of a probiotic for reducing endotoxin levels, and more particularly to the use of Lactobacillus casei GKC1 for preparing an oral composition for reducing serum endotoxin levels. [Background Technology]

[0002] An allergy is an immediate hypersensitivity reaction of the immune system to a substance. The substance that causes an allergy is also called an allergen. When the immune system is continuously exposed to an allergen, or is stimulated again by the same allergen, the immune system produces immunoglobulin (Ig) E, which is specific to that allergen. When this IgE binds to the allergen, mast cells are induced to release histamine and other chemicals, thereby triggering an allergic reaction and leading to allergic diseases.

[0003] Allergic reactions can trigger allergic symptoms in the mucous membranes, respiratory tract, skin, and / or digestive system, and in severe cases, can even lead to systemic allergic reactions. Respiratory allergies can be further divided into upper respiratory tract allergies and lower respiratory tract allergies. Upper respiratory tract allergies can cause allergic respiratory diseases such as allergic rhinitis, with symptoms including, but not limited to, sneezing, runny nose, and / or nasal congestion, and may even lead to allergic conjunctivitis with red, itchy eyes and excessive tearing. Lower respiratory tract allergies can cause allergic symptoms such as wheezing, coughing, chest tightness, and / or wheezing, and may even lead to difficulty breathing.

[0004] Common allergens that cause respiratory allergic reactions may include, but are not limited to, inhaled allergens and / or food allergens. Inhaled allergens may include, but are not limited to, mold, pollen, dust mites, cockroaches and / or animal dander, while food allergens may include, but are not limited to, peanuts, dairy products, nuts and / or seafood.

[0005] Some non-allergenic factors, although not specific allergens, can exacerbate allergic reactions. For example, for patients with allergic respiratory diseases, drastic temperature changes during seasonal transitions and / or air pollutants (such as stationary sources, mobile sources, and / or smoke from other sources) can irritate the respiratory mucosa, thus worsening allergy symptoms caused by respiratory sensitivity.

[0006] Studies have shown a positive correlation between environmental endotoxin levels and the number of patients with allergic respiratory diseases in that environment. Endotoxins originate from lipopolysaccharides (LPS) on the outer membrane of Gram-negative bacterial cells, with lipid A being the main active component. Endotoxins are released into the environment after Gram-negative bacterial cell lysis. Due to their thermal stability, endotoxins are stable in the environment and are widely present in water, air, soil, and food. Studies have found that higher endotoxin levels in the serum of patients with allergic diseases can worsen allergy symptoms. However, there is limited research on the effect of lactobacilli in reducing endotoxin levels in subjects with respiratory allergies. [Summary of the Invention]

[0007] Therefore, one aspect of the present invention is to provide the use of Lactobacillus casei GKC1 in the preparation of an oral composition for reducing serum endotoxin levels, wherein the oral composition comprises Lactobacillus casei GKC1, and when administered to a subject with respiratory allergies, it can reduce serum endotoxin levels and improve allergy symptoms.

[0008] Another aspect of the present invention is to provide the use of Lactobacillus casei GKC1 in the preparation of an oral composition for reducing serum endotoxin levels, wherein the oral composition is composed of Lactobacillus casei GKC1 and an inactive ingredient, and when administered to a subject with respiratory allergies, it can reduce serum endotoxin levels and improve allergy symptoms in the subject with respiratory allergies.

[0009] According to the above aspects of the present invention, there is a use of Lactobacillus casei GKC1 in the preparation of an oral composition for reducing the endotoxin content in serum. Lactobacillus casei GKC1 was deposited at the China General Microbiological Culture Collection Center (CGMCC) on January 12, 2018, with accession number CGMCC No. 15204.

[0010] In some embodiments of the present invention, the subject is a subject with respiratory allergy.

[0011] In some embodiments of the present invention, the oral composition may selectively comprise a food- or medically acceptable carrier, excipient, diluent, adjuvant, preservative, filler, and / or additive.

[0012] In some embodiments of the present invention, the subjects are mice, and the effective dose is from 1.0 mg / mouse / day to 10.0 mg / mouse / day.

[0013] In some embodiments of the present invention, the subject is a human being, and the effective dose is from 150 mg / 60 kg body weight / day to 1500 mg / 60 kg body weight / day.

[0014] In some embodiments of the present invention, the oral composition is administered to the subject continuously for 30 to 60 days.

[0015] In some embodiments of the present invention, after the subject was given the oral composition, the serum endotoxin level decreased, and the serum endotoxin level was 20% to 30% of the control serum endotoxin level of the control subject who was not given the oral composition.

[0016] In some embodiments of the present invention, the subjects were also exposed to smoke.

[0017] According to another aspect of the present invention, there is a use of Lactobacillus casei GKC1 in preparing an oral composition for reducing serum endotoxin levels, comprising administering an oral composition to a subject with respiratory allergies, wherein the oral composition consists of an effective dose of Lactobacillus casei GKC1 and an inactive ingredient, thereby reducing serum endotoxin levels in the subject, and the Lactobacillus casei GKC1 has the accession number CGMCC No. 15204.

[0018] In some embodiments of the present invention, after the subject was given the oral composition, the serum endotoxin level decreased, and the serum endotoxin level was 20% to 30% of the control serum endotoxin level of the control subject who was not given the oral composition.

[0019] When the Lactobacillus casei GKC1 of the present invention is administered to subjects with respiratory allergies, it can reduce the levels of allergen-specific immunoglobulin E and endotoxin in the serum of the subjects. Therefore, it can be used as an effective ingredient in oral compositions for reducing serum endotoxin levels. [Attached Image Description]

[0020] To make the above and other objects, features, advantages and embodiments of the present invention more apparent and understandable, the accompanying drawings are described in detail below: Figure 1 A bar chart showing the airway resistance of mice in the experimental and control groups of some embodiments of the present invention. Figure 2 A bar chart showing the serum OVA-IgE levels of mice in the experimental and control groups of some embodiments of the present invention. Figure 3 A bar chart showing the endotoxin content in the serum of mice in the experimental and control groups of some embodiments of the present invention.

Detailed Implementation Methods

[0021] As previously stated, the present invention provides the use of probiotics in the preparation of an oral composition for reducing serum endotoxin levels. When the probiotics are administered to a subject with respiratory allergies, they can improve the subject's airway resistance and reduce the level of allergen-specific immunoglobulin E and serum endotoxin in the subject's serum. Therefore, they can be used as an effective ingredient in an oral composition for reducing serum endotoxin levels.

[0022] The term "respiratory allergy subject" as used herein refers to a subject who experiences a respiratory allergic reaction to a specific allergen. In some embodiments, respiratory allergy symptoms may occur in the upper and / or lower respiratory tracts. In some specific examples, the upper respiratory tract includes the sinuses and / or nasal mucosa. In some specific examples, the lower respiratory tract includes the trachea, bronchi, and / or lungs. In some embodiments, the respiratory allergy subject suffers from an allergic respiratory disease, which may include, but is not limited to, asthma, bronchiectasis, chronic obstructive pulmonary disease, and / or chronic cough.

[0023] In some embodiments, the subject with respiratory allergies is not stimulated by a non-sensitizing factor. In some specific examples, the non-sensitizing factor may include, but is not limited to, smoke, wherein the source of the smoke pollution may include, but is not limited to, outdoor pollution sources or / or indoor pollution sources. The aforementioned outdoor pollution sources may include, but are not limited to, stationary sources (e.g., secondary pollutants formed by the reaction of industrial exhaust gases with sunlight), mobile sources (e.g., particulate matter emitted by motor vehicle internal combustion engines), and / or others (e.g., burning joss paper). The aforementioned indoor pollution sources may include, but are not limited to, indoor incense burning, smoking, and / or cooking. Cigarette smoke contains more than 4,000 components such as nicotine and tar, which are extremely harmful to the respiratory tract of subjects with respiratory allergies.

[0024] The aforementioned probiotic could be, for example, Lactobacillus casei GKC1, which was deposited on January 12, 2018, at the China General Microbiological Culture Collection Center (CGMCC, No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing 100101, China), with accession number CGMCCNo.15204.

[0025] In some embodiments, *Lactobacillus casei* GKC1 can be obtained, for example, through a fermentation step. The fermentation step refers to culturing *Lactobacillus casei* GKC1 using a lactic acid bacteria culture medium; the specific method is not particularly limited and can be carried out using conventional methods.

[0026] There are no particular restrictions on the type of lactic acid bacteria culture medium, as long as it can provide the nutrients required for the growth of *Lactobacillus casei* GKC1, such as carbon and nitrogen sources. In some specific examples, the carbon source may be selected from glucose, sucrose, lactose, fructose, mannose, sorbitol, glycerol, molasses, and any combination thereof. In some specific examples, the nitrogen source may be selected from soy protein, yeast extract, beef extract, casein powder, whey protein powder, fish protein hydrolysate, plant protein extract, peptone, and any combination thereof. In some specific examples, the lactic acid bacteria culture medium may be, for example, a commercially available culture medium.

[0027] There are no particular limitations on the carbon and nitrogen source content in the lactic acid bacteria culture medium, as long as it meets the growth and / or metabolic needs of *Lactobacillus casei* GKC1. In some embodiments, based on 100% by weight of the lactic acid bacteria culture medium, the medium may contain, but is not limited to, 1% to 10% by weight of carbon source, 1% to 10% by weight of nitrogen source, and a balanced amount of water. In some specific examples, the lactic acid bacteria culture medium contains 1% to 10% by weight of carbohydrates, 0.5% to 5% by weight of yeast extract, and 0.5% to 5% by weight of peptone. In some embodiments, the lactic acid bacteria culture medium may selectively contain growth stimulants, such as trace elements and / or TWEEN-80. In some embodiments, trace elements may be, for example, selected from the group consisting of magnesium ions, potassium ions, sulfate ions, hydrogen phosphite ions, and combinations thereof. In some specific examples, trace elements may be derived from magnesium sulfate and / or manganese sulfate. In some embodiments, the lactic acid bacteria culture medium may selectively contain deoxygenating agents, such as cysteine.

[0028] There are no particular limitations on the temperature and time of the fermentation step. In some embodiments, the temperature of the fermentation step is 32°C to 42°C and / or the fermentation time is 12 hours to 18 hours to enhance the growth activity of Lactobacillus casei GKC1, thereby improving its efficacy in improving allergies.

[0029] Specifically, the fermentation step involves inoculating a single colony of *Lactobacillus casei* GKC1 into a lactic acid bacteria culture medium to obtain a fermentation product. The fermentation product may include, but is not limited to, live *Lactobacillus casei* GKC1 cells, the lactic acid bacteria culture medium, and metabolites produced by the growth of *Lactobacillus casei* GKC1. In some embodiments, a solid-liquid separation step may be selectively performed on the fermentation product after the fermentation step. The method for the solid-liquid separation step is not particularly limited and may include, for example, centrifugation and / or filtration to obtain cell precipitate and / or filtration residue. In one specific example, the centrifugation step may be performed, for example, at a speed of 2000 revolutions per minute (rpm) to 12000 rpm for 2 to 15 minutes, or at 5000 rpm to 10000 rpm for 5 to 15 minutes.

[0030] In some embodiments, a drying step may be selectively performed after the solid-liquid separation step to obtain a dried product. The drying method is not particularly limited and can be carried out using conventional methods, such as freeze-drying, vacuum drying, or spray drying. It is noteworthy that the above-mentioned fermentation products, cell precipitates, filtration residues, and / or their dried products (e.g., freeze-dried powder) contain active cells of *Lactobacillus casei* GKC1, and therefore can all be used as active ingredients in oral compositions for reducing endotoxin levels in serum.

[0031] The oral composition described above contains an effective dose of Lactobacillus casei GKC1. In some embodiments, when the subject is a mouse, the effective dose may be, for example, 1.0 mg / mouse / day to 10.0 mg / mouse / day. In some embodiments, when the subject is an adult, the effective dose may be, for example, 150 mg / 60 kg body weight / day to 1500 mg / 60 kg body weight / day, such as 300 mg / 60 kg body weight / day to 1000 mg / 60 kg body weight / day, or 500 mg / 60 kg body weight / day to 800 mg / 60 kg body weight / day. Experiments have confirmed that administering Lactobacillus casei GKC1 to subjects at the above effective doses can indeed reduce the endotoxin content in the subject's serum.

[0032] In some embodiments, the oral composition may selectively comprise an inactive ingredient. In some specific examples, the inactive ingredient may comprise, but is not limited to, food- or medically acceptable carriers, excipients, diluents, adjuvants, preservatives, fillers, and / or additives. In some embodiments, the oral composition may, for example, consist of Lactobacillus casei GKC1 and the inactive ingredient.

[0033] In some embodiments, the oral composition is administered to the subject continuously for 30 to 60 days to reduce the endotoxin level in the subject's serum. In some embodiments, the oral composition is administered to the subject simultaneously with sensitization, challenge, and / or stimulation by a non-sensitizing factor. Sensitization can be achieved, for example, by repeatedly stimulating the subject's immune system through contact, ingestion, and / or injection. Challenge can be achieved, for example, by stimulating the subject's nasal cavity and / or respiratory tract in powder and / or physical form.

[0034] Experiments have confirmed that administration of Lactobacillus casei GKC1 to subjects with respiratory allergies can improve airway resistance and reduce serum levels of allergen-specific immunoglobulin E and endotoxins. Specifically, the airway resistance in subjects treated with Lactobacillus casei GKC1 was 40% to 60% that of control subjects who did not receive Lactobacillus casei GKC1.

[0035] Secondly, the level of allergen-specific immunoglobulin E in the serum of subjects with respiratory allergies treated with Lactobacillus casei GKC1 was 40% to 60% of the level of allergen-specific immunoglobulin E in the control serum of subjects who did not receive Lactobacillus casei GKC1.

[0036] Furthermore, the endotoxin levels in the serum of subjects treated with Lactobacillus casei GKC1 were 20% to 30% higher than those in the control serum of subjects who were not treated with Lactobacillus casei GKC1.

[0037] The following examples illustrate the application of the present invention, but they are not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Example 1: Source of the strain

[0038] Lactobacillus casei GKC1 was purchased from CGMCC. The accession number for Lactobacillus casei GKC1 is CGMCC No. 15204. It was isolated from human breast milk. The microbiological properties and culture methods of Lactobacillus casei GKC1 are described in Chinese Patent Application Publication No. CN118105411A, which is also listed as a reference here. Hereinafter, Lactobacillus casei GKC1 will be referred to as strain GKC1. Example 2: Preparation of freeze-dried powder of strain GKC1

[0039] A single colony of strain GKC1 was inoculated into a culture medium and fermented in an anaerobic environment at 37°C for 18 hours to obtain a liquid culture. The culture medium contained 1% to 10% glucose, 0.1% to 5% yeast extract, 0.1% to 0.5% peptone, 0.01% to 2.00% trace elements, 0.01% to 0.10% cysteine, 0.05% to 1.00% TWEEN80, and a balanced amount of water. The trace elements were selected from the group consisting of magnesium ions, potassium ions, sulfate ions, hydrogen phosphite ions, and combinations thereof. It should be noted that the type of culture medium does not affect the efficacy of strain GKC1, and the culture media listed above are not intended to limit the invention.

[0040] Next, 5 wt% to 20 wt% skim milk powder was added to the liquid culture, and the mixture was centrifuged at 1000 rpm to 15000 rpm to obtain the bacterial cells of strain GKC1. The bacterial cells of strain GKC1 were then freeze-dried to obtain a lyophilized powder of strain GKC1. It should be noted that the freeze-drying was performed solely for the purpose of facilitating administration, quantification, and preservation, and is not intended to limit the scope of the invention. Example 3: Evaluation of the efficacy of lyophilized strain GKC1 in improving airway resistance and reducing serum levels of allergen-specific immunoglobulin E and endotoxins in subjects. 1. Establishing an animal model

[0041] Five-week-old BALB / c mice were housed in an individually ventilated caging system. The temperature was maintained at 22±2℃, and the humidity at 40% to 60%. The light and dark periods were each 12 hours. During the rearing period, the mice had free access to feed and sterile reverse osmosis water.

[0042] After a two-week acclimatization period (i.e., when the mice were 7 weeks old), the mice were randomly divided into an experimental group and a control group, with 4 mice in each group, and the experiment was conducted for 57 consecutive days. During the experiment, the lyophilized powder of strain GKC1 was administered to the mice in the experimental group daily at a dose of 4.5 mg / mouse / day, equivalent to 660 mg per day for a 60 kg adult. Physiological experimental water was administered to the mice in the control group.

[0043] From day 0 to day 12 of the experiment, mice in both the experimental and control groups were administered ovalbumin (OVA) antigen via intraperitoneal injection daily to obtain OVA-sensitized mice. The OVA agent was obtained by uniformly mixing 500 μg / mL of OVA with an incomplete Freund's adjuvant at a 1:1 ratio, followed by filtration through a sterile filter membrane. OVA is the major antigen of egg white and can act as a specific allergen.

[0044] From day 17 to day 23 of the experiment, the respiratory tracts of mice in both the experimental and control groups were challenged daily with nebulized OVA for 1 minute. From day 24 to day 54 of the experiment, mice in both the experimental and control groups were exposed to an environment containing cigarette smoke for 10 minutes daily. Cigarette smoke is a non-sensitizing irritant that can damage the respiratory tracts of mice, thereby exacerbating the allergic symptoms in the respiratory tracts of OVA-sensitized mice. 2. Evaluation Methods 2.1 Airway resistance test

[0045] On days 55 and 56 of the experiment, airway resistance was tested in mice in both the experimental and control groups using a whole body plethysmography (WBP) system (manufacturer: DataSciences International, Minnesota, USA; product name: Buxco). Specifically, during respiration, the humidity and temperature of the air change as it enters and exits the mouse's respiratory organs, and these changes further affect the surrounding air pressure. The WBP has a closed cavity equipped with a highly sensitive pressure sensor, allowing it to detect subtle pressure changes within the cavity caused by the mouse's respiration. The enhanced pause (Penh) value was then obtained using a barometric method.

[0046] During the airway resistance test, the baseline Penh value was first obtained. This value was measured when the mouse was placed in the closed chamber of the WBP and exposed to nebulized physiological saline (i.e., 0.9% w / v NaCl aqueous solution) for 3 minutes. Next, the Penh value was obtained... Mch The Penh value is measured when mice are exposed to a nebulized dose of 6.25 mg / mL methacholine (for 3 minutes), which stimulates bronchial constriction. Airway resistance can be expressed as a ratio of Penh values. Mch The Penh value (numerator) is the ratio of the baseline Penh value (denominator). A higher Penh value indicates greater airway resistance and more severe respiratory allergic symptoms in mice. 2.2 Antibody detection in serum

[0047] On day 57 of the experiment, mice in both the experimental and control groups were sacrificed, and blood was collected to detect the level of OVA-specific immunoglobulin E (OVA-IgE) in mouse serum using an enzyme-linked immunosorbent assay (ELISA). The assay was briefly described as follows: a coating buffer was prepared using an appropriate amount of anti-mouse OVA-IgE monoclonal antibody and coating buffer. Then, 100 μL / well of the coating buffer was used to coat a Nunc 96-well immunomicroplate (Nunc-Immuno). TM Micro Well TMThe wells were coated with 96-well plates and incubated overnight (12 to 18 hours) at 4°C. After removing the residual liquid, the wells were rinsed with washing buffer (phosphate-buffered saline, PBS) to remove any uncoated monoclonal antibodies. The wells were then blocked with 200 μL / well blocking buffer at room temperature (15°C to 35°C) for 1 hour, after which the residual liquid was removed.

[0048] Next, 100 μL of OVA-IgE standard solution and 100-fold dilution of the serum to be tested were added to each well, and then incubated at room temperature for 1 hour. After rinsing the wells with washing buffer, 100 μL of biotin-inoculated secondary antibody was added to each well, and the wells were incubated at room temperature for 1 hour, followed by rinsing with washing buffer. Then, 100 μL of 3,3',5,5'-tetramethylbenzidine (TMB) acceptor solution was added to each well, and the wells were incubated for 15 minutes. Finally, 50 μL of H2SO4 was added to each well to terminate the reaction.

[0049] The absorbance of the OVA-IgE standard solution was measured at a wavelength of 450 μm to plot a standard curve. The absorbance of the serum to be tested was then measured at a wavelength of 450 μm, and the content of OVA-IgE in the serum to be tested was calculated by interpolation. 2.3 Detection of endotoxin content in serum

[0050] The endotoxin content in mouse serum was detected using recombinant factor C endpoint fluorescence assays. The method is briefly described below: Anti-lipid A antibody binds to endotoxin, activating recombinant factor C (rFC) to rFC'. rFC' can further hydrolyze synthetic substances into colored or fluorescent zymogens. Therefore, the endotoxin content in mouse serum can be quantified using colorimetric or fluorescence methods. 2.4 Statistical Analysis

[0051] The experimental results are expressed as mean and standard deviation (SD), and statistical analysis was performed using commercially available software (Microsoft Excel 2010). The results were analyzed using t-tests, and α was set at 0.05 as the significance level (i.e., p-value < 0.05 indicates statistical significance). 3. Evaluation Results 3.1 Changes in body weight of mice in the experimental and control groups

[0052] During the experiment, the body weight of mice in the experimental and control groups was measured and recorded every two weeks, and the results are listed in Table 1.

[0053] Table 1 Group experimental group control group p-value Day 0 26.1±2.0 25.5±1.2 0.653 Day 14 27.7±2.4 27.5±1.2 0.863 Day 28 27.9±1.7 27.9±1.0 1.000 Day 42 28.9±1.8 27.6±1.1 0.332 Day 56 29.6±1.4 28.4±1.1 0.266

[0054] As shown in Table 1, the weight of mice in both the experimental and control groups increased steadily during the experiment, and there was no statistically significant difference in weight between the two groups. 3.2 Airway resistance in mice of the experimental and control groups

[0055] Please see Figure 1 It is a bar chart showing the airway resistance of mice in the experimental and control groups of some embodiments of the present invention, where the horizontal axis represents the group, the vertical axis represents the airway resistance as a ratio of Penh values, and the symbol "**" indicates p<0.01.

[0056] like Figure 1 As shown, the ratio of Penh values ​​in the experimental group was approximately 2, while the ratio of Penh values ​​in the control group was approximately 4. The ratio of Penh values ​​in the experimental group was significantly lower than that in the control group, and the ratio of Penh values ​​in the experimental group was approximately 50% of that in the control group. This indicates that the freeze-dried powder of strain GKC1 can indeed improve airway resistance in OVA-sensitized mice and has the function of protecting the airway and reducing airway damage. 3.3 Serum OVA-IgE levels in mice of the experimental and control groups

[0057] Please see Figure 2 The graph shows the serum OVA-IgE content of mice in the experimental and control groups of some embodiments of the present invention. The horizontal axis represents the group, the vertical axis represents the serum OVA-IgE content (unit: ng / mL), and the symbol "*" indicates p<0.05.

[0058] like Figure 2 As shown, the serum OVA-IgE level in the experimental group mice was significantly lower than that in the control group. Specifically, the serum OVA-IgE level in the experimental group mice was approximately 50% of that in the control group mice, indicating that the lyophilized GKC1 strain can indeed reduce the level of allergen-specific immunoglobulin E in the serum of OVA-sensitized mice, and has the potential to reduce macrocell-induced allergic reactions. 3.4 Serum endotoxin levels in experimental and control mice

[0059] Please see Figure 3 The graph shows the serum endotoxin content of mice in experimental and control groups according to some embodiments of the present invention. The horizontal axis represents the group and the vertical axis represents the serum endotoxin content in units of endotoxin units (EU) / mL. The symbol "*" indicates p<0.05.

[0060] like Figure 3 As shown, the endotoxin levels in the experimental group mice were lower than those in the control group mice, and the difference between the two groups was statistically significant. Furthermore, the endotoxin levels in the experimental group mice were 25% lower than those in the control group, indicating that the lyophilized GKC1 strain can indeed reduce the endotoxin levels in the serum of OVA-sensitized mice.

[0061] In summary, the specific live bacterial morphology, preparation method, experimental model animal, and evaluation method described above are merely illustrative of the use of *Lactobacillus casei* GKC1 of the present invention in preparing oral compositions for reducing serum endotoxin levels. However, those skilled in the art will understand that other live bacterial morphologies, other preparation methods, other experimental model animals, and other evaluation methods can also be used for the use of *Lactobacillus casei* GKC1 of the present invention in preparing oral compositions for reducing serum endotoxin levels without departing from the spirit and scope of the invention, and are not limited to the above. For example, without affecting the efficacy of *Lactobacillus casei* GKC1 in reducing serum endotoxin levels, the live bacterial morphology of *Lactobacillus casei* GKC1 can be fermentation product, cell precipitate, filtration residue, and / or lyophilized powder.

[0062] As can be seen from the above embodiments, the use of Lactobacillus casei GKC1 in the preparation of oral compositions for reducing serum endotoxin levels has the advantage that, when using Lactobacillus casei GKC1, it not only improves the airway resistance of the subject, but also reduces the content of allergen-specific immunoglobulin E and serum endotoxin in the subject's serum. It can be used as an effective ingredient in oral compositions for reducing serum endotoxin levels and can be applied to improve allergic symptoms of allergic respiratory diseases.

[0063] While the present invention has been disclosed above with reference to several specific embodiments, various modifications, alterations, and substitutions can be made to the foregoing disclosure. It should be understood that, without departing from the spirit and scope of the invention, certain features of the embodiments of the invention may be used in some cases, but other features may not be used accordingly. Therefore, the spirit and scope of the invention should not be limited to the embodiments described above.

Claims

1. The use of Lactobacillus casei GKC1 in the preparation of an oral composition for reducing endotoxin levels in the serum of a subject, characterized in that, The Lactobacillus casei GKC1 was deposited at the China General Microbiological Culture Collection Center (CGMCC) on January 12, 2018, with accession number CGMCC No. 15204.

2. The use as described in claim 1, characterized in that, The subjects were those with respiratory allergies.

3. The use as described in claim 1, characterized in that, The oral composition further comprises food- or medically acceptable carriers, excipients, diluents, adjuvants, preservatives, fillers, and / or additives.

4. The use as described in claim 1, characterized in that, The subjects were mice, and the effective dose was 1.0 mg / mouse / day to 10.0 mg / mouse / day.

5. The use as described in claim 1, characterized in that, The subjects were human, and the effective dose was 150 mg / 60 kg body weight / day to 1500 mg / 60 kg body weight / day.

6. The use as described in claim 1, characterized in that, The oral composition is administered to the subject continuously for 30 to 60 days.

7. The use as described in claim 1, characterized in that, After the subjects were given the oral composition, the endotoxin content in their serum decreased, and the endotoxin content in their serum was 20% to 30% of the endotoxin content in the serum of control subjects who were not given the oral composition.

8. The use as described in claim 1, characterized in that, The subjects were also exposed to smoke.

9. The use of Lactobacillus casei GKC1 in the preparation of an oral composition for reducing endotoxin levels in the serum of a subject, characterized in that, The oral composition administered to the subject comprises an effective dose of Lactobacillus casei GKC1 and an inactive ingredient, thereby reducing the endotoxin content in the subject's serum, wherein the Lactobacillus casei GKC1 has the accession number CGMCC No. 15204.

10. The use as described in claim 9, characterized in that, After the subjects were given the oral composition, the endotoxin content in their serum decreased, and the endotoxin content in their serum was 20% to 30% of the endotoxin content in the serum of control subjects who were not given the oral composition.

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