Bifidobacterium longum and preparation thereof for relieving colorectal cancer

Abstract

The application relates to the field of microbial technology, and discloses application of Bifidobacterium longum and a preparation thereof in relieving colorectal cancer, wherein the Bifidobacterium longum is Bifidobacterium longum (ATCC 33323) Bifidobacterium longum ​ ) ZZR-JX-11, which was preserved in the China Center for Type Culture Collection on May 17, 2024, at an address of Wuhan University, No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province, and a preservation number of CCTCC NO: M 2024981. Through the technical scheme, the problems of poor acid resistance of the Bifidobacterium longum and poor relieving effect on the colorectal cancer in the related art are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microorganisms, in particular, to application of Bifidobacterium longum and a preparation thereof in relieving colorectal cancer. BACKGROUND

[0002] In recent years, the role of intestinal microbial community in human health and disease has been increasingly concerned. There are trillions of microorganisms in the human intestine, which form a complex symbiotic ecosystem with the host and participate in the regulation of many physiological functions of the human body. As a typical representative of intestinal probiotics, Bifidobacterium longum plays a key role in maintaining intestinal barrier function, regulating immune response and promoting nutrient metabolism.

[0003] However, the existing Bifidobacterium longum on the market focuses on improving intestinal digestive function, and there is still a great lack of Bifidobacterium longum strains and related applications for this specific application scenario of relieving colorectal cancer. Moreover, the existing Bifidobacterium longum has poor acid tolerance and weak effect on relieving colorectal cancer. Bifidobacterium longum of different sources and different subspecies has great differences in biological characteristics and functional activity. Therefore, it is necessary to provide a Bifidobacterium longum with significant effect on relieving colorectal cancer and acid tolerance. SUMMARY

[0004] The present application provides application of Bifidobacterium longum and a preparation thereof in relieving colorectal cancer, solving the problems of poor acid tolerance and poor effect on relieving colorectal cancer of Bifidobacterium longum in the related art.

[0005] The technical solutions of the present application are as follows:

[0006] The present application provides a Bifidobacterium longum, which is Bifidobacterium longum (Bifidobacterium longum) Bifidobacterium longum Bifidobacterium longum ) ZZR-JX-11, which was preserved in China Center for Type Culture Collection on May 17, 2024, at an address of Wuhan University, No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province, China, with a preservation number of CCTCC NO: M 2024981.

[0007] As a further technical solution, the 16S rRNA gene sequence of the Bifidobacterium longum (Bifidobacterium longum) Bifidobacterium longum ) ZZR-JX-11 is shown in SEQ ID NO. 1.

[0008] As a further technical solution, the 16S rRNA gene sequence of the Bifidobacterium longum (Bifidobacterium longum) Bifidobacterium longum ) ZZR-JX-11 is as follows:

[0009]

[0010] The present invention also proposes a microbial agent, wherein the microbial agent comprises the aforementioned Bifidobacterium longum ( Bifidobacterium longum ZZR-JX-11.

[0011] As a further technical solution, the microbial agent includes bacterial powder and / or probiotic solid beverage.

[0012] As a further technical solution, when the microbial agent is solid, the Bifidobacterium longum ( Bifidobacterium longum The addition amount of ZZR-JX-11 in the microbial agent shall not be less than 1×10⁻⁶. 8 CFU / g; when the microbial agent is non-solid, the Bifidobacterium longum ( Bifidobacterium longum The addition amount of ZZR-JX-11 in the microbial agent shall not be less than 1×10⁻⁶. 8 CFU / mL.

[0013] The present invention also proposes the application of the aforementioned Bifidobacterium longum or the aforementioned microbial agent in the preparation of drugs for alleviating colorectal cancer.

[0014] The present invention also proposes the application of the aforementioned Bifidobacterium longum or the aforementioned microbial agent in the preparation of drugs that regulate the increase of prognostic tumor suppressor gene expression in colorectal cancer patients or in the preparation of drugs that regulate the decrease of prognostic oncogene expression in colorectal cancer patients.

[0015] The present invention also proposes the application of the aforementioned Bifidobacterium longum or the aforementioned microbial agent in dairy product fermentation and intestinal health regulation.

[0016] The present invention also proposes the application of the aforementioned Bifidobacterium longum or the aforementioned microbial agent in the preparation of drugs that sensitize against oxaliplatin chemotherapy for colorectal cancer.

[0017] The present invention also proposes the use of the aforementioned Bifidobacterium longum or the aforementioned microbial agent in the preparation of drugs that inhibit the number and / or volume of colorectal cancer tumors.

[0018] The working principle and beneficial effects of this invention are as follows:

[0019] The long bifidobacterium ZZR-JX-11 in the present application is obtained by purification from feces, and is identified by strain morphology and molecular biology, and by simulating a gastric juice environment, it is measured that the long bifidobacterium ZZR-JX-11 has good acid resistance; through cell proliferation experiments, colony formation experiments, a small mouse colorectal tumor experiment induced by dextran sodium sulfate+AOM, a sensitization effect of colorectal cancer chemotherapy and the like, it is concluded that the long bifidobacterium ZZR-JX-11 can significantly inhibit colorectal tumors, and the ZZR-JX-11 combined with oxaliplatin can play a synergistic effect and synergistically reduce tumor volume. BRIEF DESCRIPTION OF DRAWINGS

[0020] The present application will be further described in detail below in combination with the drawings and specific embodiments.

[0021] Figure 1 It is a plate culture diagram of the long bifidobacterium ZZR-JX-11 in Example 1 of the present application.

[0022] Figure 2 It is a strain morphology diagram of the long bifidobacterium ZZR-JX-11 in Example 1 of the present application.

[0023] Figure 3 It is a phylogenetic tree diagram of the long bifidobacterium ZZR-JX-11 in Example 1 of the present application.

[0024] Figure 4 It is a cell proliferation experiment result diagram in Example 4 of the present application.

[0025] Figure 5 It is a colony formation experiment result diagram in Example 4 of the present application.

[0026] Figure 6 It is a sensitization experiment result diagram of colorectal cancer chemotherapy in Example 4 of the present application.

[0027] Wherein Con is a control group, the strain is a ZZR-JX-11 group, oxaliplatin is an oxaliplatin group, and the strain+oxaliplatin is a ZZR-JX-11+oxaliplatin group.

[0028] Figure 7 It is an electron microscope detection result diagram of the exosome of the long bifidobacterium ZZR-JX-11 in Example 4 of the present application.

[0029] Biological material preservation instructions

[0030] The long bifidobacterium (Bifidobacterium longum) Bifidobacterium longum ) ZZR-JX-11 provided in the present application is preserved in the China Center for Type Culture Collection, the preservation address is No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province, Wuhan University, the preservation number is CCTCC NO: M 2024981, and the preservation date is May 17, 2024. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] Preparation method of GAM medium (HB8518-1): Weigh 49.0g (HB8518-1), heat and dissolve in 1000mL distilled water, autoclave at 121℃ for 15 minutes, cool to 50℃, add 1mL of sterile 0.1% vitamin K1 solution (HB8462a) and 1mL of heme chloride (5mg / mL) (2100500) to every 1000mL of medium, add 5mg of filtered sterile mupirocin lithium salt (HB0384-6a) to every 100mL of medium, mix well and set aside.

[0033] Preparation method of TOS selective medium (HB9213): Weigh 62.5g (HB9213), heat to boiling and completely dissolve in 1000mL distilled water, dispense into Erlenmeyer flasks, 100mL per flask, autoclave at 115℃ for 15 minutes, cool to 50℃, add 5mg of filtered sterilized mupirocin lithium salt (HB0384-6a) to every 100mL of medium, add the medium to petri dishes or glass test tubes and allow it to cool.

[0034] Example 1: Screening and Identification of Strains

[0035] 1.1 Screening and purification of strains

[0036] 1.1.1 Filtering

[0037] Take 1g of fecal matter into a sterile tube, serially dilute it with sterile PBS, and take 10g of each solution. -3 10 -4 10 -5 100 μL of each of the three dilution gradients was evenly spread on TOS selective medium and incubated anaerobically at 37°C for 48 h for purification.

[0038] 1.1.2 Purification

[0039] Single colonies were isolated by streaking from TOS selective medium and inoculated into GAM medium. The colonies were then anaerobically cultured at 37°C for 24 hours. After incubation, the purity of the colonies was examined under a microscope. If contaminating bacteria were still found, the streaking, picking, incubation, and microscopic examination steps were repeated until a pure single strain was obtained.

[0040] 1.1.3 Cryopreservation

[0041] Take the bacterial culture from GAM medium in good growth condition, add 500 μL each of the bacterial culture and 50% glycerol sterilized by autoclaving to a cryovial, shake well, place in a programmed cell cryopreservation box, and then put in a -80℃ freezer to obtain cryopreserved Bifidobacterium longum ZZR-JX-11.

[0042] 1.2 Identification of strains

[0043] 1.2.1 Identification of strain morphology

[0044] The selected Bifidobacterium longum ZZR-JX-11 was inoculated on GAM medium and cultured at 37℃ for 24 h. The size, shape, color, gloss, raised shape, transparency, and edge characteristics of the colonies were observed under a microscope (1000X).

[0045] Results: The plate culture image of Bifidobacterium longum ZZR-JX-11 is shown below. Figure 1 As shown, the morphology of Bifidobacterium longum strain ZZR-JX-11 is as follows: Figure 2 As shown, through Figure 2 Analysis shows that Bifidobacterium longum ZZR-JX-11 is a straight or slightly curved rod-shaped organism with a blunt, rounded end, and exists singly or in pairs.

[0046] 1.2.2 Identification of the strain by molecular biology

[0047] The cryopreserved *Bifidobacterium longum* ZZR-JX-11 from section 1.1.3 was sent to Wuhan Tianyi Huayu Gene Technology Co., Ltd. for sequencing. Based on the obtained 16S rRNA sequence, a BLAST search was performed in GenBank to identify homologous sequences. The results showed that it was similar to *Bifidobacterium longum* (…). Bifidobacterium longum The homology is as high as 100%, and the 16S rRNA gene sequence of *Bifidobacterium longum* ZZR-JX-11 is shown in SEQ ID No. 1. A Neighbor-Joining phylogenetic tree of *Bifidobacterium longum* ZZR-JX-11 constructed with *Micrococcus luteus* DSMZ 20030 (AJ536198) as an outbranch, based on the 16S rRNA gene sequence alignment results, is shown below. Figure 3 As shown.

[0048] Example 2 Physiological and biochemical characteristics of the strain

[0049] 2.1 Determination of enzyme activity of the strain

[0050] The enzyme activity of Bifidobacterium longum ZZR-JX-11 was determined using conventional methods in this field.

[0051] Table 1. Results of enzyme activity assay for Bifidobacterium longum ZZR-JX-11

[0052]

[0053] Note: "+" is a positive reaction; "-" is a negative reaction.

[0054] As shown in Table 1, B. longum ZZR-JX-11 has significant glycosidase and short-chain esterase activity, and is suitable as a dietary fiber metabolism-type probiotic. The strain has great potential in the fields of dairy product fermentation, intestinal health regulation, and functional ingredient conversion.

[0055] 2.2 Determination of acid production from carbon sources by the strain

[0056] The acid production from carbon sources by the strain was determined by using conventional methods in the art.

[0057] Table 2 Determination results of acid production from carbon sources by B. longum ZZR-JX-11

[0058]

[0059] Note: "+" is a positive reaction; "-" is a negative reaction.

[0060] As shown in Table 2, B. longum ZZR-JX-11 has high acid production capacity from monosaccharides, disaccharides, and part of oligosaccharides, and is suitable as a candidate for dairy product fermentation agent or probiotic.

[0061] Example 3 Determination of acid tolerance of the strain

[0062] 3.1 Strain recovery

[0063] (1) Preparation before test: 37℃ water bath, high-pressure culture medium, anaerobic culture bag, anaerobic bag, shaking tube, and biological safety cabinet for ultraviolet irradiation sterilization for 30 min.

[0064] (2) Take one shaking tube and add 9 mL of mupirocin lithium salt GAM medium (preparation method as described above for the preparation method of GAM medium (HB8518-1));

[0065] (3) Take one frozen B. longum ZZR-JX-11, place it in a 37℃ water bath, gently shake it, and after complete thawing, take out the frozen tube, sterilize it with alcohol, and then, in the biological safety cabinet, after passing the alcohol lamp, open the frozen tube, and inject the bacterial solution into the shaking tube, and blow it evenly;

[0066] (4) Cover the shaker tube with the lid (do not tighten the lid), put it into a sterilized anaerobic bag in advance, and put it into a 2.5L anaerobic bag. Tighten the bag and put it into a 37℃ incubator for 24-48h. When the OD600nm of the MRS culture medium is distributed in 1.2-1.5, the viable cell count is carried out to obtain the bacterial liquid, which is stored in a 4℃ refrigerator for standby.

[0067] 3.2 Strain acid tolerance determination

[0068] (1) After centrifugation of the bacterial liquid in 3.1(4) above, resuspend the bacteria with sterile physiological saline (or PBS) and count, then dilute the bacterial liquid with sterile physiological saline (or PBS) to 10 10 CFU / 200μL.

[0069] (2) Set up experimental and control groups:

[0070] Experimental group: Sterile measuring cylinder (or sterile pipette) to take 10mL artificial gastric juice for standby. Artificial gastric juice is purchased from Solabio, artificial gastric juice SGF (sterile), item number: A7921.

[0071] Control group: Sterile measuring cylinder (or sterile pipette) to take 10mL physiological saline or PBS for standby.

[0072] (3) Take 200μL of bacterial liquid and add it to the experimental or control group. Mix well and incubate at 37℃, and start timing.

[0073] (4) Stop the experiment at 1h, 2h and 3h respectively. Divide each tube into 3 parts and measure the absorbance and viable cell count. Calculate the survival rate of Bifidobacterium longum ZZR-JX-11 after artificial gastric juice treatment. Survival rate = (experimental group viable cell count after experiment - control group viable cell count after experiment) / viable cell count before experiment x 100%,

[0074] Method for determining viable cells:

[0075] (1) Blow and mix the bacterial liquid. Take 100μL of the bacterial liquid after dilution and observe the bacterial morphology under a microscope and count;

[0076] (2) Take 1mL of the mixed bacterial liquid and add it to a centrifuge tube containing 9mL of physiological saline. Mix well by inverting. Prepare a 10 -1 dilution. Take 1mL of the 10 -1 dilution to prepare a 10 -2 dilution. Dilute successively to 10 -9 dilution,

[0077] Take 10 -6 , 10 -7 , 10 -8 , 10-9 4 dilutions of the diluent each 0.1 mL in an agar plate, evenly spread, put the plate and anaerobic bag into an anaerobic bag, seal. Put into a 37°C constant temperature incubator for anaerobic culture for 24h, the number of viable bacteria CFU / mL = the actual average of the plate count × 10 × the dilution factor. After the density is appropriate, centrifuge at 3000rpm for 5min, resuspend and inoculate in 25mL medium for culture, and carry out subsequent experiments, and the survival rate at 1h, 2h and 3h is determined by measuring absorbance and microscopic counting;

[0078] Absorbance: Prepare a 96-well plate, add 100 microliters of the bacteria to be tested to each well, and measure OD 600nm The numerical value is OD=1, about 10 8 CFU / mL.

[0079] Microscopic counting: Dilute the bacteria liquid to an appropriate multiple, stain with trypan blue, drop into a bacterial counting plate, and count under a microscope.

[0080] The determination results are shown in the following table;

[0081] Table 3 Determination results of strain acid tolerance

[0082]

[0083] As can be seen from Table 3, the Bifidobacterium longum ZZR-JX-11 has good acid tolerance.

[0084] Example 4 Determination of strain inhibition of colorectal cancer

[0085] 4.1 Cell proliferation experiment

[0086] (1) Add 100 microliters of colorectal cancer cell SW1463 suspension to each well of a 96-well plate, and usually add about 1000 colorectal cancer cells SW1463 to each well in a cell proliferation experiment.

[0087] (2) The colorectal cancer cells SW1463 were incubated in a 37°C 5% CO2 cell incubator for 24 hours.

[0088] (3) After 8 hours of co-culture with Bifidobacterium longum ZZR-JX-11, antibiotics (100u / mL penicillin and 100ug / mL streptomycin) were added to terminate.

[0089] (4) After incubation in a 37°C cell incubator containing 5% CO2 air and 100% humidity (the incubation time is according to the reagent instruction time), 10 microliters of CCK-8 solution were added to each well.

[0090] (5) After adding CCK-8, place the 96-well plate back into a 37°C, 5% CO2 incubator and incubate for 1-4 hours. Different cell types may require different incubation times; generally, OD... 450nm The linearity is optimal when the value is between 0.8 and 1.5.

[0091] (6) Use an ELISA reader to measure the absorbance (OD value) of each well at 450 nm.

[0092] Colorectal cancer cells SW1463 that were not treated with Bifidobacterium longum ZZR-JX-11 were used as a control group.

[0093] Empty culture medium was used as a blank and was designated as the blank group.

[0094] (7) Calculate cell viability. Cell viability = (ODsample - ODblank) / (ODcontrol - ODblank) × 100%. The measurement results are as follows: Figure 4 As shown.

[0095] Depend on Figure 4 It can be seen that when the viable count of Bifidobacterium longum ZZR-JX-11 of the present invention is ≥1×10⁻⁶, 9 CFU can inhibit the survival of colorectal cancer cells.

[0096] 4.2 Colony Formation Experiment

[0097] (1) SW1463 colorectal cancer cells in the logarithmic growth phase were seeded in 6-well plates at a rate of 600 cells / well.

[0098] (2) Colorectal cancer cells SW1463 were co-cultured with Bifidobacterium longum ZZR-JX-11 for 8 hours and then antibiotics (100u / mL penicillin and 100μg / mL streptomycin) were added to terminate the culture.

[0099] (3) Colorectal cancer cells SW1463 were cultured continuously for 2 weeks.

[0100] (4) After washing with PBS solution, fix with 4wt% paraformaldehyde solution for 3 hours, then add crystal violet staining solution to each well for cell staining. After 20 minutes, wash with ddH2O and air dry. Count clones in each well, perform statistical analysis, and the results are as follows: Figure 5 As shown.

[0101] Depend on Figure 5 It is known that the Bifidobacterium longum ZZR-JX-11 of the present invention can inhibit cell colony formation, and as the number of viable Bifidobacterium longum ZZR-JX-11 increases, cell colony formation can be significantly inhibited.

[0102] 4.3 Inhibitory effect of strain ZZR-JX-11 on colorectal tumor formation induced by dextran sodium sulfate salt + AOM in mice

[0103] 5-week-old Balb / c mice were purchased and normally fed for one week before the experiment.

[0104] Specifically, 2 mg / mL streptomycin was administered in the drinking water for three days before the experiment; on the first day of the experiment, the mice were intraperitoneally injected with 200 μL of 10 mg / kg AOM (control and intervention groups) or normal saline (pure negative control); the ZZR-JX-11 intervention group was administered 10 9 CFU / 200 μL by gavage once a day; the control group was administered the same volume of normal saline by gavage until the end of the experiment. After one week, i.e., at 7 weeks of age, the mice were fed with 2% DSS drinking water or normal drinking water, and at 8 weeks of age, the mice were fed with normal drinking water for a total of 3 cycles. Then, the mice were fed with normal drinking water, and the mice were sacrificed at 14, 16, and 18 weeks of age, respectively.

[0105] Grouping: control group (AOM / DSS treatment + PBS gavage with normal saline), ZZR-JX-11 (10 9 CFU / 200 μL) intervention group (AOM / DSS treatment + ZZR-JX-11 gavage), with 15 mice in each group.

[0106] The differences in tumor number and volume between the ZZR-JX-11 intervention group and the control group were compared.

[0107] The results are shown in the following table.

[0108] Table 4 Inhibitory effect of the strain on colorectal tumor formation in mice

[0109]

[0110] As can be seen from Table 4, compared with the saline control group, the number of tumors in the ZZR-JX-11 intervention group was significantly reduced, and the volume of single tumors was also significantly reduced. This indicates that B. longum ZZR-JX-11 has a significant inhibitory effect on the occurrence and development of colorectal tumors.

[0111] 4.4 Tumor-related gene regulation characteristics of the strain

[0112] RNA was extracted from tumor tissues and cells using the Trizol method to verify RNA quality. The NEBNext® Ultra™ RNA Library Prep Kit was used to construct libraries from qualified RNA, and quantitative analysis was performed to verify library quality. Sequencing was performed using the Illumina sequencing platform to obtain raw data. Sequence annotation was completed through data quality control and sequence alignment. Differential expression analysis was performed using the DESeq2 and edgeR programs in R. The results are shown in the table below.

[0113] Table 5. Regulatory effects of bacterial strains on the expression of colorectal cancer-related genes.

[0114]

[0115] As shown in Table 5, high expression of DDX60 and TREH, as tumor suppressor genes, is associated with better prognosis, and Bifidobacterium longum ZZR-JX-11 can promote their expression.

[0116] 4.5 Sensitizing effect of strain ZZR-JX-11 on chemotherapy for colorectal cancer

[0117] A mouse subcutaneous xenograft colorectal cancer model was established using the CT26 cell line.

[0118] Balb / c mice aged 6-8 weeks were inoculated with CT26 cells and randomly divided into a control group, a ZZR-JX-11 group, an oxaliplatin group, and a ZZR-JX-11 + oxaliplatin group. One week before modeling, mice were given physiological saline and 10... 9 CFU / 200μL ZZR-JX-11 was administered by gavage (200μL). Oxaliplatin 10mg / kg was started on the third day of modeling. Specific procedure: Mice were subcutaneously injected with 1×10 mg / kg of ZZR-JX-11 in the right inguinal region. 6 CT26 cells. After injection, gently press with a sterile cotton swab for a moment to prevent cells from flowing out along the injection site; a slight bulge of skin at the inoculation site will be visible. Monitor mouse weight changes and tumor size after implantation. The experiment is terminated one month after modeling. Tumor size is measured using calipers, and the longest diameter (a) and the maximum transverse diameter (b) perpendicular to the tumor are measured. The result is expressed as V (mm). 3 ) = ab 2 / 2 Calculate the tumor volume; the measurement results are as follows: Figure 6 As shown.

[0119] pass Figure 6 Analysis shows that Bifidobacterium longum ZZR-JX-11 has a certain anti-colorectal cancer tumor effect. When Bifidobacterium longum ZZR-JX-11 and oxaliplatin are used in combination, the tumor volume reduction is significantly greater than when the two are used alone, indicating that the combination of Bifidobacterium longum ZZR-JX-11 and oxaliplatin can have a synergistic effect.

[0120] 4.6 Exosome of the strain ZZR-JX-11

[0121] After the B. longum ZZR-JX-11 is cultured for 16-20 hours, 100-200 mL of supernatant is taken, low-temperature centrifuged by a high-speed centrifuge (100,000 rpm), rinsed with PBS, and then electron microscopy detection is performed.

[0122] The electron microscopy detection result is shown in Table 5. Figure 7 As can be seen from Table 5, the B. longum ZZR-JX-11 is a B. longum capable of secreting vesicles. Figure 7

[0123] In addition, the B. longum ZZR-JX-11 of the present application can also secrete the following human homologous functional protein polypeptides, as shown in the following table, by mass spectrometry detection.

[0124] Table 6: Information of human homologous protein polypeptides secreted by the strain

[0125]

[0126] As can be seen from Table 6, the B. longum ZZR-JX-11 can also secrete the human homologous functional protein polypeptides in the above table, which can provide nutrients for the beneficial bacteria in the intestinal tract, regulate the balance of intestinal flora, and directly or indirectly activate the intestinal immune system, improve the intestinal immune function, promote the absorption of nutrients by the intestinal tract, and have many other benefits.

[0127] The above merely describes the preferred embodiments of the present application, but should not be used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.​

Claims

1. Bifidobacterium longum, characterized in that, Bifidobacterium longum is Bifidobacterium longum (ATCC 15697) Bifidobacterium longum The Bifidobacterium longum can be applied in the preparation of a drug for regulating the expression of a cancer-related gene related to the prognosis of a colorectal cancer patient or in the preparation of a drug for regulating the expression of a cancer-promoting gene related to the prognosis of a colorectal cancer patient. ) ZZR-JX-11, deposited in the China Center for Type Culture Collection on May 17, 2024, at an address of Wuhan University, No. 299, Bayi Road, Wuchang District, Wuhan, Hubei Province, China, and having a deposit number of CCTCC NO: M 2024981. The Bifidobacterium longum can be applied in the preparation of a drug for sensitizing oxaliplatin chemotherapy of colorectal cancer. Bifidobacterium longum 2. A microbial inoculant characterized in that, The microbial agent includes Bifidobacterium longum (Bifidobacterium longum) of claim 1 Bifidobacterium longum ) ZZR-JX-11.

3. The microbial inoculant of claim 2, wherein, When the microbial agent is solid, the Bifidobacterium longum ( Bifidobacterium longum The addition amount of ZZR-JX-11 in the microbial agent shall not be less than 1×10⁻⁶. 8 CFU / g; when the microbial agent is non-solid, the Bifidobacterium longum ( 4. The Bifidobacterium longum of claim 1 or the microbial agent of any one of claims 2-3 for use in the preparation of a drug for alleviating colorectal cancer. The addition amount of ZZR-JX-11 in the microbial agent shall not be less than 1×10⁻⁶. 8 CFU / mL. ​

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