Bifidobacterium animalis subsp. Lactis CCMXJ2003 as well as composition and application thereof

Abstract

The invention discloses bifidobacterium animalis subsp. Lactis CCMXJ2003 as well as a composition and application thereof, and belongs to the technical field of microbial preparations. In order to screen a specific probiotic strain which can form efficient synergy with 2 '-fucosyllactose and has good viability and an immunoregulation function, and construct a precise micro-ecological intervention scheme aiming at atopic dermatitis immunopathology key links, the invention provides a microecological intervention method for the atopic dermatitis immunopathology key links. The invention provides the bifidobacterium animalis subsp. Lactis CCMXJ2003 capable of efficiently utilizing the 2 '-fucosyllactose, and an in-vivo experiment proves that the composition of the 2'-fucosyllactose and the bifidobacterium animalis subsp. Lactis CCMXJ2003 shows an obvious enhancement effect in the aspect of relieving the specific dermatitis; the compound has a wide application prospect in prevention and / or treatment of atopic dermatitis.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of microbial preparations, and particularly relates to a strain of animal Bifidobacterium lactis subsp. CCMXJ2003, a composition thereof and application thereof. BACKGROUND

[0002] Atopic dermatitis (AD) is a common chronic, recurrent, inflammatory skin disease, and is characterized by severe pruritus and eczematous skin rash. The disease not only seriously affects the quality of life of patients, but also often accompanies anxiety, depression, sleep disorders and other comorbidities, bringing heavy health burden to patients' families and society. Global epidemiological surveys show that the prevalence of atopic dermatitis in the child population is as high as 10%-30%, and in adults, it is also as high as 1%-10%. Most patients develop the disease in infancy (especially within 6 months after birth), and about 25% of cases will persist into adulthood, showing a long-term recurrent clinical course.

[0003] The etiology of atopic dermatitis is complex, and is the result of the interaction of multiple factors such as genetic susceptibility, environmental triggers, immune system disorders, and skin and intestinal microbiota disorders. In the pathogenesis, skin barrier dysfunction and abnormal immune response are particularly important: damaged keratinocytes release immune modulators such as thymic stromal lymphopoietin (TSLP), activate Langerhans cells and dendritic cells, and then drive Th2 dominant immune response, leading to excessive production of inflammatory mediators (such as IL-4, IL-13, IgE), causing persistent itching and skin damage. In recent years, research has further revealed that the intestinal-skin axis plays an important role in the occurrence and development of atopic dermatitis. Intestinal flora imbalance can damage the integrity of the intestinal mucosal barrier, trigger the "leaky gut" phenomenon, and allow enterogenous inflammatory mediators and bacterial metabolites to enter the circulatory system, continuously stimulating systemic immune response and exacerbating Th2 pathway activation and skin inflammation.

[0004] Notably, the establishment of intestinal flora in early life is closely related to the risk of atopic dermatitis. Clinical studies have confirmed that children with atopic dermatitis often show reduced intestinal flora diversity, with increased abundance of potential pathogenic bacteria such as Klebsiella and Escherichia coli, and significantly reduced beneficial flora such as Bifidobacterium and Bacteroides. This imbalance in flora may affect the normal development and regulation of the immune system, increasing the tendency to allergy.

[0005] Breastfeeding is widely recognized to reduce the risk of infant atopic dermatitis, which is not only related to the nutritional support of breast milk, but also due to its rich bioactive components, especially human milk oligosaccharides (HMOs). As the most abundant HMOs, 2'-Fucosyllactose (2'-FL) accounts for about 30% of the total amount of HMOs in breast milk, and has been shown to have significant immunomodulatory and prebiotic functions. On the one hand, 2'-FL can regulate local and systemic immune responses by directly interacting with intestinal pathogens or host immune cells, promote immune system maturation, and significantly reduce the risk of IgE-related allergic diseases; on the other hand, 2'-FL can be used as a metabolic substrate for specific beneficial bacteria to promote their growth and colonization. However, existing studies have shown that the species of Bifidobacterium that can effectively utilize 2'-FL are limited, mainly concentrated in Bifidobacterium longum subsp. infantis, Bifidobacterium bifidum, Bifidobacterium breve and some Bifidobacterium longum subsp. longum. Notably, in animal Bifidobacterium, Bifidobacterium animalis ), no strain has been found that can efficiently metabolize 2'-FL, suggesting that this species may have unique genetic or physiological differences in 2'-FL metabolism. Animal Bifidobacterium is an important member of intestinal probiotics, with excellent acid and bile salt tolerance and potential immunomodulatory capacity, but its synergistic effect with 2'-FL in the prevention and treatment of atopic dermatitis has not been fully explored.

[0006] Based on the above status quo, the prevention and treatment of atopic dermatitis still faces many challenges: existing therapies mostly focus on symptom control (such as topical glucocorticoids, immunosuppressants, etc.), often difficult to fundamentally regulate immune imbalance and dysbiosis, and long-term use may be associated with adverse reactions. Regulating the gut-skin axis through nutritional or microecological intervention has become a new strategy for the prevention and treatment of atopic dermatitis, but the existing combination of probiotics and prebiotics still has limitations in strain specificity, synergistic efficiency and mechanism clarity. Specifically, how to select specific probiotic strains that can form high-efficiency synergy with 2'-FL, with good survival ability and immunomodulatory function, and construct a precise microecological intervention scheme targeting the key links of atopic dermatitis immune pathology (especially Th2 immune bias and intestinal barrier dysfunction), is a technical problem that needs to be solved in this field. In particular, can the combination of animal Bifidobacterium and 2'-FL produce unexpected synergistic effects to effectively prevent or alleviate atopic dermatitis, and is the mechanism of action different from known 2'-FL utilizing strains, all of which need to be further researched and developed. SUMMARY

[0007] To screen specific probiotic strains capable of forming high-efficiency synergy with 2'-FL, having good survival ability and immune regulation function, and construct a precise microecological intervention scheme for the key link of atopic dermatitis immunopathology (especially Th2 immune bias and intestinal barrier disorder), the present application first proposes to combine Bifidobacterium animalis lactis subsp. Bifidobacterium animalis subsp. lactis ) and 2'-fucosyllactose for preventing and / or relieving atopic dermatitis.

[0008] To solve the above technical problems and achieve the corresponding technical effects, the present application provides the following technical solutions: The first object of the present application is to provide a strain of Bifidobacterium animalis lactis subsp. Bifidobacterium animalis subsp. lactis ) CCMXJ2003, which is preserved in the Guangdong Microbial Culture Collection Center, with the preservation number GDMCC No: 66938, the preservation date September 9, 2025, and the address of the preservation unit being the 5th floor of Building 59, 100 Middle Martyrs Road, Guangzhou, and the Institute of Microbiology, Guangdong Academy of Sciences.

[0009] The second object of the present application is to provide the use of the above-mentioned Bifidobacterium animalis lactis subsp. CCMXJ2003 in the preparation of a medicament for preventing and / or relieving atopic dermatitis, which includes any one of the following effects: 1) reducing serum IgE levels and inhibiting IgE-mediated immune responses; 2) effectively inhibiting the abnormal expression of Th2-type inflammatory factors such as TSLP, IL-4, and IL-13, promoting the secretion of Th1-type characteristic inflammatory factor IFN-γ, and regulating Th1 / Th2 cytokine balance; 3) reducing dermal inflammatory cell infiltration and improving skin barrier function; 4) regulating intestinal flora balance, promoting the colonization of beneficial bacteria, and reducing the generation of potentially harmful bacteria; 5) promoting the generation of short-chain fatty acids.

[0010] In one embodiment of the present application, the number of viable bacteria of Bifidobacterium animalis lactis subsp. CCMXJ2003 in the medicament is not less than 1x10 8 CFU / mL or 1x10 8 CFU / g.

[0011] The third object of the present application is to provide a composition for preventing and / or relieving atopic dermatitis, which contains the above-mentioned Bifidobacterium animalis lactis subsp. CCMXJ2003 and 2'-fucosyllactose.

[0012] In one embodiment of the present application, the viable count of Bifidobacterium animalis lactis CCMXJ2003 in the composition is not less than 1 x 10 8 CFU / mL or 1 x 10 8 CFU / g.

[0013] In one embodiment of the present application, the concentration of 2'-fucosyllactose in the composition is 5%-10%.

[0014] In one embodiment of the present application, the composition further comprises a food-acceptable carrier or excipient, which comprises one or more of diluents, stabilizers or lyophilization protectants.

[0015] The composition can be used as a solution by directly dissolving 2'-fucosyllactose in a bacterial solution of Bifidobacterium animalis lactis CCMXJ2003 to form a mixture.

[0016] In one embodiment of the present application, the fourth object of the present application is to provide the use of the above-mentioned composition in the preparation of a medicament for preventing and / or alleviating atopic dermatitis, which comprises any one of the following effects: a) reducing serum IgE levels and inhibiting IgE-mediated immune responses; b) effectively inhibiting the abnormal expression of Th2-type inflammatory factors such as TSLP, IL-4 and IL-13, promoting the secretion of Th1-type characteristic inflammatory factor IFN-γ, and regulating the balance of Th1 / Th2 cytokines; c) reducing dermal inflammatory cell infiltration and improving skin barrier function; d) regulating intestinal flora balance, promoting the colonization of beneficial bacteria, and reducing the generation of potentially harmful bacteria; e) promoting the production of short-chain fatty acids.

[0017] The fifth object of the present application is to provide a medicament for preventing and / or alleviating atopic dermatitis, which contains the above-mentioned composition.

[0018] In one embodiment of the present application, the viable count of Bifidobacterium animalis lactis CCMXJ2003 in the medicament is not less than 1 x 10 8 CFU / mL or 1 x 10 8 CFU / g, and the concentration of 2'-fucosyllactose is 5%-10%.

[0019] In one embodiment of the present application, the dosage form of the medicament is a solution, a suspension, a powder, a tablet, a capsule or an emulsion.

[0020] The beneficial effects of the present application are: This invention provides a strain of *Bifidobacterium animalis* subsp. *lactobacter* CCMXJ2003 that can efficiently utilize 2'-fucosylated lactose, exhibiting both good gastrointestinal tolerance and thermal stability. Using a mouse model of atopic dermatitis, this invention revealed that the combination of 2'-fucosylated lactose and *Bifidobacterium animalis* subsp. *lactobacter* CCMXJ2003 showed a significantly enhanced effect in alleviating atopic dermatitis compared to either 2'-fucosylated lactose or CCMXJ2003 alone. Specifically, it effectively repaired the epidermal barrier structure, reversed pathological thickening of the dermis and abnormal keratinization; significantly inhibited the Th2 inflammatory cascade mediated by IgE secretion disorders, TSLP overexpression, and abnormal activation of IL-4 / IL-13; and promoted Th1 immune homeostasis. Furthermore, LEfSe combined with LDA analysis revealed that this composition specifically increases the abundance of beneficial bacteria and butyric acid-producing bacteria while inhibiting pathogen-associated flora. Correlation analysis further showed that elevated butyric acid levels were significantly positively correlated with the abundance of beneficial bacteria and significantly negatively correlated with the abundance of pathogenic bacteria. The mechanism of action of this combination involves gut-skin axis regulation mediated by gut microbiota remodeling and short-chain fatty acid metabolism, achieving multi-dimensional intervention from skin physical barrier repair and systemic immune regulation to microbial community ecological balance, thereby significantly improving atopic dermatitis symptoms.

[0021] The composition provided by this invention offers a novel, safe, and effective nutritional intervention method for alleviating atopic dermatitis, demonstrating broad application prospects.

[0022] Preservation of biological materials: The animal Bifidobacterium lactis subsp. (Bifidobacterium animalis) of this invention Bifidobacterium animalis subsp. lactis CCMXJ2003 is deposited at the Guangdong Provincial Center for Microbial Culture Collection, with accession number GDMCC No: 66938, deposited on September 9, 2025. The address of the depository is 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou, Guangdong Academy of Sciences Institute of Microbiology. Attached Figure Description

[0023] Figure 1 The figure shows the results of in vitro utilization of 2'-fucosylated lactose by Bifidobacterium animalis subsp. Lactobacillus CCMXJ2003. Figure 2 The severity of atopic dermatitis in the right ear of mice in each group is shown in the image. Figure 3 The image shows the results of measuring the thickness of the right ear of mice in each group; Figure 4 The results of the dermatitis lesion scores in the right ear of mice in each group are shown in the figure. Figure 5Figures of H&E and Toluidine blue staining results of right ear tissues of mice in each group; Figure 6 Figures of statistical results of dermis thickness of right ear of mice in each group; Figure 7 Figures of statistical results of mast cell number of right ear of mice in each group; Figure 8 Figures of detection results of IgE level in serum of mice in each group; Figure 9 Figures of detection results of TSLP level in right ear tissues of mice in each group; Figure 10 Figures of detection results of inflammatory factors IL-4, IL-13 and IFN-γ levels in right ear tissues of mice in each group; wherein, Figure 10 A in the figures is a figure of detection results of inflammatory factor IL-4 level in right ear tissues of mice in each group, Figure 10 B in the figures is a figure of detection results of inflammatory factor IL-13 level in right ear tissues of mice in each group, Figure 10 C in the figures is a figure of detection results of inflammatory factor IFN-γ level in right ear tissues of mice in each group; Figure 11 Figures of intestinal flora structure of mice in each group; wherein, Figure 11 A in the figures is a figure of intestinal flora structure of mice in each group at the level of door, Figure 11 B in the figures is a figure of intestinal flora structure of mice in each group at the level of genus; Figure 12 Figures of detection results of short-chain fatty acid level in fecal samples of mice in each group; wherein, Figure 12 A in the figures is a figure of detection results of acetic acid level in fecal samples of mice in each group, Figure 12 B in the figures is a figure of detection results of propionic acid level in fecal samples of mice in each group, Figure 12 C in the figures is a figure of detection results of butyric acid level in fecal samples of mice in each group; Figure 13 Figures of correlation analysis results between differential intestinal flora and key short-chain fatty acids. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with specific embodiments and the accompanying drawings. It should be noted that the following embodiments are only used to explain the present application but not to limit the scope of the present application. The following embodiments are only a part of the embodiments of the present application but not all the embodiments. Those skilled in the art can refer to the content herein, appropriately improve the process parameters to achieve the purpose of the present application. It should be particularly pointed out that all similar replacements and changes are obvious to those skilled in the art, and they are considered to be included in the present application. The method and application of the present application have been described by the preferred embodiments, and the relevant personnel can obviously modify or appropriately change and combine the method and application described herein without departing from the content and scope of the present application to realize and apply the present application technology. In the art, other technicians obtain the embodiments without creative labor, which are protected by the present application.

[0025] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, culture medium and instruments used are conventional materials, reagents, culture medium and instruments in the art unless otherwise specified, which can be obtained by commercial channels by those skilled in the art.

[0026] The 2'-fucosyllactose used in the present application is a food-grade raw material with a purity of not less than 99% and is suitable for preparing oral preparations.

[0027] Example 1: Isolation and identification of animal bifidobacterium lactis subsp. CCMXJ2003 The stool of a healthy infant was taken as a sample, gradient dilution method was used to spread on MRS anaerobic selective medium containing 0.5% cysteine, after 48 h culture at 37℃, the single colony of gram-positive bacillus with "Y" or "V" shape was selected, the pure culture of Bifidobacterium strain was obtained, and the strain number was numbered, one of the obtained Bifidobacterium strains was numbered as CCMXJ2003; the genomic DNA of the strain was extracted, the specific primers Bif-groEL-F (SEQ ID NO. 1: 5'-TCCGATTACGAYCGYGAGAAGCT-3') and Bif-groEL-R (SEQ ID NO. 2: 5'-CSGCYTCGGTSGTCAGGAACAG-3') of Bifidobacterium were used for PCR amplification with the genomic DNA as a template, the reaction program was as follows: 95℃ pre-denaturation for 10 min; 95℃ denaturation for 30 s, 58℃ annealing for 30 s, 72℃ extension for 60 s (30 cycles); 72℃ final extension for 10 min. The PCR amplified product was spotted in 1.0% agarose gel hole, and the amplification result (about 500 bp) was observed in the gel electrophoresis instrument under the condition of voltage 120 V for 30 min, the amplification successful strain was sent to Xinjiang Youkang Biotechnology Co., Ltd. for sequencing, and the obtained sequence was compared with NCBI database by BLAST, and the strain CCMXJ2003 was determined as Bifidobacterium animalis lactis subsp. Bifidobacterium animalis subsp. lactis ). The strain was preserved in Guangdong Microbial Culture Collection Center, the preservation number was GDMCC No: 66938, the preservation date was September 9, 2025, and the address of the preservation unit was the 5th floor of No. 59 Building, 100 Middle Martyrs Road, Guangzhou, Institute of Microbiology, Guangdong Academy of Sciences.

[0028] Example 2: Detection of in vitro utilization ability of Bifidobacterium animalis lactis CCMXJ2003 to 2'-fucosyllactose The basic MRS medium without glucose and other carbon sources was used as the fermentation base, 1% (w / v) 2'-fucosyllactose was supplemented as the only carbon source in the experimental group, 1% (w / v) glucose was supplemented in the positive control group, and no carbon source was added in the negative control group. After inoculation of strain CCMXJ2003, it was cultured at 37℃ under anaerobic condition for 24 h, the optical density was determined every 3 h, and the in vitro utilization ability of Bifidobacterium animalis lactis CCMXJ2003 to 2'-fucosyllactose was observed.

[0029] The results obtained in this example were analyzed, and the results were as follows Figure 1As shown: the growth rate and maximum cell density of the experimental strain were significantly higher than those of the negative control group (p<0.01), and there was no significant difference with the positive control group (p>0.05), proving that the Bifidobacterium animalis lactis CCMXJ2003 can effectively utilize 2'-fucosyllactose as a carbon source for proliferation.

[0030] Example 3: Environmental tolerance evaluation of Bifidobacterium animalis lactis CCMXJ2003 1. Gastric acid / choline salt tolerance test The activated two-generation strain CCMXJ2003 bacterial solution was centrifuged at 4℃, 6000xg for 15 min, the precipitate was taken and washed three times, and resuspended in PBS buffer with pH 3.0 (gastric acid tolerance test) or PBS buffer with pH 8.0 and containing 0.3% (w / v) choline salt (choline salt tolerance test); the resuspended bacterial solution was incubated at 37℃ under anaerobic conditions for 4 h, and sampled at 0 h and 4 h, respectively, and the viable cell count was determined by plate colony counting method, and the survival rate of the strain was calculated.

[0031] Survival rate (%) = [logN1 / logN0] x 100%; In the formula, N1: viable cell count at 4 h; N0: viable cell count at 0 h.

[0032] The results obtained in this experiment were analyzed, and the results are shown in Table 1: the survival rate of Bifidobacterium animalis lactis CCMXJ2003 under gastric acid (pH 3.0) conditions was 90.89±1.03%, and the survival rate under choline salt (0.3% concentration) conditions was 91.33±1.84, indicating that the strain had good tolerance to acid and choline salt.

[0033] 2. High temperature tolerance test The activated two-generation strain CCMXJ2003 bacterial solution was placed in a constant temperature incubator at 30, 37, 40, 45, and 50℃, respectively, and cultured for 24 h, and the OD 600nm value was determined.

[0034] The results obtained in this experiment were analyzed, and the results are shown in Table 2: the OD 600nm of Bifidobacterium animalis lactis CCMXJ2003 under 37℃ conditions reached 0.92, and the growth was best; the OD 600nm under 30℃ and 40℃ conditions were both higher than 0.80, and the growth was good; it still showed strong tolerance under high temperature conditions of 45℃, with OD 600nm of 0.75; and the growth was significantly inhibited under 50℃ conditions, with OD 600nmless than 0.20. The results show that the animal Bifidobacterium lactis subsp. CCMXJ2003 can grow well in the temperature range of 30-45°C, showing excellent temperature adaptability, especially good tolerance at high temperature of 45°C, which embodies its outstanding advantages in temperature adaptability.

[0035] Table 1. High-temperature tolerance test results of animal Bifidobacterium lactis subsp. CCMXJ2003

[0036] Example 4: Application of 2'-fucosyllactose and animal Bifidobacterium lactis subsp. CCMXJ2003 in synergistically relieving atopic dermatitis in mice The atopic dermatitis model of mice was established by exposing the skin to calcipotriol (MC903), and the experimental groups and specific modeling methods are as follows: 40 SPF 3-week-old female BALB / c mice (body weight 12-14 g) were randomly divided into 5 groups (n=8) after 1 week of adaptive feeding: blank control group (CON), model group (MOD), animal Bifidobacterium lactis subsp. CCMXJ2003 alone intervention group (Bif), 2'-fucosyllactose alone intervention group (2'-FL), and animal Bifidobacterium lactis subsp. CCMXJ2003 and 2'-fucosyllactose combined intervention group (Bif+2'-FL). The blank control group and the model group were orally gavaged with 0.2 mL of sterile normal saline daily; the animal Bifidobacterium lactis subsp. CCMXJ2003 alone intervention group was gavaged with 0.2 mL of animal Bifidobacterium lactis subsp. CCMXJ2003 bacterial solution daily, which was obtained by inoculating animal Bifidobacterium lactis subsp. CCMXJ2003 in MRS liquid medium and culturing to 1×10 8 CFU / mL; the 2'-fucosyllactose alone intervention group was gavaged with 0.2 mL of 7% 2'-fucosyllactose solution daily; and the animal Bifidobacterium lactis subsp. CCMXJ2003 and 2'-fucosyllactose combined intervention group was gavaged with 0.2 mL of animal Bifidobacterium lactis subsp. CCMXJ2003 bacterial solution containing 7% (w / v) 2'-fucosyllactose (1×10 8 CFU / mL) daily, for 4 weeks. At the 3rd week after the start of gavage intervention, atopic dermatitis modeling was started simultaneously, and 20 μL of absolute ethanol was applied to the right ear of the CON group of mice daily, and 20 μL of MC903 solution (dissolved in absolute ethanol, concentration 2 nmol / L) was applied to the right ear of the MOD group, Bif group, 2'-FL group, and Bif+2'-FL group of mice daily, for continuous modeling for 14 days.

[0037] The right ear thickness of the mice was measured, and the skin lesion score was performed 14 days after modeling, and then the mice were sacrificed, and the fecal samples were collected and stored at -80°C for 16S rRNA gene sequencing analysis of intestinal flora and short-chain fatty acid production by internal standard method. Before sacrifice, blood samples were collected and centrifuged to separate serum, which was stored at -80°C after aliquoting, and the IgE level in the serum of the mice was determined by ELISA; after sacrifice, the right ear tissue of the mice was taken, a part of which was fixed with 4% paraformaldehyde for tissue section, and H&E staining and toluidine blue staining were used respectively to observe the dermal thickness and the number of mast cells in the right ear section of the mice under a biological microscope, and the rest of the tissue was made into a homogenate, and the levels of TSLP, IL-4, IL-13 and IFN-γ were determined by ELISA.

[0038] The results obtained in this example were analyzed, and the results are shown in Figures 2-13 The lesion degree of specific dermatitis of the ears of the mice in each group is shown in Figure 2 The mice in the MOD group showed typical symptoms of specific dermatitis, including significant scabbing, erythema and desquamation; the clinical symptoms of each intervention group were reduced to varying degrees: the mice in the Bif group showed scabbing and desquamation, accompanied by mild erythema; the mice in the 2'-FL group mainly showed scale shedding and mild erythema, but no scabbing was observed; and the mice in the Bif+2'-FL combined intervention group had normal ear skin condition, and no obvious erythema, desquamation or scabbing was observed, and the clinical performance was significantly better than that of the other intervention groups. The above results show that 2'-fucosyllactose single intervention can alleviate the symptoms of specific dermatitis to some extent, but its combination with animal bifidobacterium subspecies CCMXJ2003 shows the best synergistic therapeutic effect, which can effectively reduce the lesion degree of specific dermatitis in mice.

[0039] The ear thickness of the mice in each group is shown in Figure 3 The mice in the MOD group showed severe ear thickening symptoms; compared with the MOD group, the ear thickness of the mice in the Bif, 2'-FL and Bif+2'-FL intervention groups was significantly reduced (p<0.0001), and the mice in the Bif+2'-FL combined intervention group only showed slight thickening. Although the difference in ear thickness between the three intervention groups did not reach statistical significance, the ear thickness of the Bif+2'-FL group was reduced by 17.4% compared with the Bif single intervention group and by 7.8% compared with the 2'-FL single intervention group, which indicates that the combination of Bif and 2'-FL shows a synergistic effect in alleviating ear thickening caused by specific dermatitis.

[0040] The skin lesion score of the ears of the mice in each group is shown in Figure 4 ​As shown in FIG. 6, compared with the MOD group, the Bif, 2'-FL and Bif+2'-FL intervention groups could significantly reduce the ear dermatitis injury score (p<0.01 or p<0.0001); the ear dermatitis injury score of the Bif+2'-FL combined intervention group was not significantly different from that of the 2'-FL group, but was significantly lower than that of the single Bif intervention group (p<0.01), indicating that the combined intervention significantly alleviated the ear dermatitis and had a synergistic enhancement effect in improving the ear symptoms.

[0041] The H&E and toluidine blue staining results of the right ear tissues of the mice in each group are shown in FIG. 7. Figure 5 As shown in FIG. 7, compared with the MOD group, the Bif, 2'-FL and Bif+2'-FL intervention groups could significantly reduce the dermal thickness (p<0.0001). The Bif+2'-FL combined intervention showed a synergistic enhancement effect in reducing the dermal thickness, and the effect was significantly better than that of the Bif or 2'-FL single intervention (p<0.0001). The toluidine blue staining results showed that the number of mast cells in the dermal layer of the MOD group was significantly increased, while the infiltration degree of each intervention group was effectively reduced; among them, the inhibition effect of the Bif+2'-FL group on the infiltration of mast cells was significantly stronger than that of the Bif single intervention group (p<0.01), and there was no significant difference with the 2'-FL single intervention group (p>0.05). Figure 6 and Figure 7 This indicates that the Bif and 2'-FL combined intervention has a significant synergistic effect in alleviating the dermal thickening, inflammatory cell infiltration and repairing skin damage of the mice with atopic dermatitis.

[0042] The detection results of the IgE level in the serum of the mice in each group are shown in FIG. 8. Figure 8 As shown in FIG. 8, compared with the MOD group, the 2'-FL intervention group and the Bif+2'-FL combined intervention group could significantly reduce the IgE level in the serum of the mice (p<0.0001). The effect of the Bif+2'-FL combined intervention group in reducing the IgE level was significantly better than that of the Bif single intervention group (p<0.001), but there was no significant difference with the 2'-FL single intervention.

[0043] The detection results of the TSLP level in the right ear tissues of the mice in each group are shown in FIG. 9. Figure 9 As shown in FIG. 9, compared with the MOD group, the Bif, 2'-FL and Bif+2'-FL combined intervention could significantly inhibit the TSLP level in the ear tissues (p<0.0001). Among them, the inhibition effect of the Bif+2'-FL combined intervention on TSLP was significantly better than that of the Bif or 2'-FL single intervention (p<0.01), indicating that the combined intervention of the two had a synergistic enhancement effect in regulating the expression of TSLP.

[0044] The detection results of the inflammatory factors IL-4, IL-13 and IFN-γ levels in the right ear tissues of the mice in each group are shown in FIG. 10. Figure 10As shown in FIG. 6, compared with the MOD group, the levels of Th2-type related cytokines IL-4 and IL-13 were significantly reduced in each intervention group (p<0.01 or p<0.001 or p<0.0001), and there was no significant difference between the intervention groups. The levels of Th1-type cytokine IFN-γ in all intervention groups were significantly higher than those in the MOD group (p<0.01 or p<0.0001), and the level of IFN-γ in the Bif+2'-FL combined intervention group was significantly higher than that in the Bif (p<0.0001) and 2'-FL (p<0.05) single intervention groups. The above results show that the Bif+2'-FL combined intervention can synergistically inhibit Th2-type immune response, while enhancing Th1-type immune response, thereby effectively restoring Th1 / Th2 immune balance and relieving the pathological symptoms related to atopic dermatitis.

[0045] The structure of the intestinal flora of mice in each group is shown in FIG. 7. Figure 11 As shown in FIG. 7, at the phylum level, the MOD group showed typical characteristics of ecological imbalance, with abnormal increase in the abundance of Bacillota and Pseudomonadota, and significant decrease in the abundance of Bacteroidota, resulting in significant increase in the F / B ratio. Single supplementation of BIF or 2'-FL can reduce the F / B ratio and the abundance of Pseudomonadota; while the BIF and 2'-FL combined intervention showed the most significant synergistic regulation effect, not only effectively reversing the abnormal F / B ratio and Pseudomonadota abundance, but more importantly, restoring them to the level comparable to that of the CON group (FIG. 7A). Figure 11 At the genus level, the MOD group was enriched in a variety of potential pathogenic bacteria, such as Enterococcus, Proteus, and Staphylococcus, etc.; 2'-FL single intervention can specifically inhibit the growth of Proteus and increase the abundance of Muribaculaceae and Lactobacillus; Bif single intervention significantly increases the abundance of Lactobacillaceae and Muribaculaceae, etc., which have anti-inflammatory and barrier maintenance functions; combined intervention further restructures the healthy flora structure, forming a dominant community with Bacteroidales, Muribaculaceae, Lactobacillus, and Pediococcus as the core, which reflects a significant ecological synergistic regulation effect (FIG. 7B). Figure 11

[0046] The detection results of the level of short-chain fatty acids in the fecal samples of mice are shown in FIG. 8. Figure 12 ​As shown, the levels of acetic acid, propionic acid, and butyric acid in the feces of mice in the MOD group were significantly lower than those in the CON group (p<0.0001), indicating that the short-chain fatty acid metabolism capacity of the intestinal flora was impaired under atopic dermatitis conditions. All intervention groups showed varying degrees of improvement: Bif alone significantly increased the levels of acetic acid, propionic acid, and butyric acid (p<0.0001), while 2'-FL alone significantly increased the levels of acetic acid, propionic acid, and butyric acid (p<0.0001). The combined intervention of Bif and 2'-FL showed the best effect, with acetic acid, propionic acid, and butyric acid levels significantly higher than those in the MOD group (p<0.0001). Furthermore, propionic acid levels were significantly higher than in the 2'-FL alone group (p<0.01), and butyric acid levels were significantly higher than in both the 2'-FL and Bif alone groups (p<0.0001), indicating a clear synergistic effect of Bif + 2'-FL in promoting butyric acid production.

[0047] The correlation analysis results between differential gut microbiota and key short-chain fatty acids are as follows: Figure 13 As shown: butyric acid and Enterococcus Abundance showed a significant negative correlation (p=0.0097) with... Staphylococcus It showed a negative correlation trend and a significant positive correlation with norank_f__Muribaculaceae (p=0.028). Acetic acid was negatively correlated with multiple bacterial groups, including norank_f__Muribaculaceae. Lactobacillus , Pediococcus Prevotellaceae_UCG-001 Enterococcus Lachnospiraceae_NK4A136 Alistipes , Odoribacter ,and Roseburia Etc. Propionic acid and Staphylococcus and Enterococcus A significant negative correlation was observed (p=0.003). Existing research indicates that gut microbiota can produce short-chain fatty acids through the fermentation of undigested proteins and amino acids. In this study, using an MC903-induced atopic dermatitis model, elevated butyrate levels were highly associated with an increase in norank_f__Muribaculaceae and a decrease in Enterococci. This result suggests that butyrate may improve the microenvironment by remodeling the gut microbiota structure: namely, promoting the proliferation of beneficial bacteria such as norank_f__Muribaculaceae and inhibiting the growth of potentially pathogenic bacteria such as Enterococci. Based on these findings, in an atopic dermatitis model, elevated gut butyrate levels may indirectly mediate its anti-inflammatory effect on the skin through the aforementioned microbiota remodeling and microenvironment improvement.

[0048] The above merely describes the preferred embodiments of the present application, and it should be pointed out that, for those skilled in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as falling within the protection scope of the present application.

Claims

1. A strain of Bifidobacterium animalis subsp. lactis ( Bifidobacterium animalis subsp. lactis CCMXJ2003, characterized in that, The accession number is GDMCC No: 66938.

2. The use of Bifidobacterium animalis subsp. Lactobacillus CCMXJ2003 as described in claim 1 in the preparation of a medicament for the prevention and / or relief of atopic dermatitis, characterized in that, The drug has any of the following effects: 1) Reduce serum IgE levels and inhibit IgE-mediated immune responses; 2) Effectively inhibits the abnormal expression of inflammatory factors TSLP, IL-4 and IL-13, promotes the secretion of IFN-γ, a characteristic Th1 inflammatory factor, and regulates the balance of Th1 / Th2 cytokines; 3) Reduces inflammatory cell infiltration in the dermis and improves skin barrier function; 4) Regulates the balance of intestinal flora, promotes the colonization of beneficial bacteria, and reduces the generation of potentially harmful bacteria; 5) Promotes the formation of short-chain fatty acids.

3. The application according to claim 2, characterized in that, The viable count of Bifidobacterium animalis subsp. lactis CCMXJ2003 in the drug is not less than 1×10⁻⁶. 8 CFU / mL or 1×10 8 CFU / g.

4. A composition for preventing and / or alleviating atopic dermatitis, characterized in that, The composition contains Bifidobacterium animalis subsp. lactis CCMXJ2003 as described in claim 1 and 2'-fucosylated lactose.

5. The composition according to claim 4, characterized in that, The viable count of Bifidobacterium animalis subsp. lactis CCMXJ2003 in the composition is not less than 1×10⁻⁶. 8 CFU / mL or 1×10 8 CFU / g.

6. The composition according to claim 4, characterized in that, The concentration of 2'-fucosylated lactose in the composition is 5%-10%.

7. The use of the composition according to any one of claims 4-6 in the preparation of a medicament for the prevention and / or relief of atopic dermatitis, characterized in that, The drug has any of the following effects: a) Reduce serum IgE levels and inhibit IgE-mediated immune responses; b) Effectively inhibits the abnormal expression of inflammatory factors TSLP, IL-4 and IL-13, promotes the secretion of IFN-γ, a characteristic inflammatory factor of Th1, and regulates the balance of Th1 / Th2 cytokines; c) Reduce inflammatory cell infiltration in the dermis and improve skin barrier function; d) Regulate the balance of intestinal flora, promote the colonization of beneficial bacteria, and reduce the generation of potentially harmful bacteria; e) Promotes the formation of short-chain fatty acids.

8. A medicament for the prevention and / or relief of atopic dermatitis, characterized in that, The drug contains the composition of claim 4.

9. The medicament according to claim 8, characterized in that, The viable count of Bifidobacterium animalis subsp. lactis CCMXJ2003 in the drug is not less than 1×10⁻⁶. 8 CFU / mL or 1×10 8 CFU / g, the concentration of 2'-fucosylated lactose is 5%-10%.

10. The medicament according to claim 8, characterized in that, The dosage form of the drug is a solution, suspension, powder, tablet, capsule or emulsion.

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