Construction method of lactobacillus murine induced mouse irritable bowel syndrome model

Abstract

The invention discloses a construction method of a model for inducing a mouse irritable bowel syndrome by using lactobacillus murine. According to the method, a mouse irritable bowel syndrome model is established by giving a certain amount of lactobacillus acidophilus to a mouse. According to the present invention, the Lactobacillus murine is adopted as the inducing bacterium of the mouse irritable bowel syndrome model, such that the clinical manifestation of the irritable bowel syndrome, such as visceral sensitivity, colon transmission speed, defecation amount and the like, can be rapidly and stably replicated, and the Lactobacillus murine can be used for the subsequent research of the irritable bowel syndrome.

Description

Technical Field

[0001] The invention belongs to the technical field of animal model construction, and particularly relates to a method for constructing a mouse irritable bowel syndrome model induced by Lactobacillus murine. Background Art

[0002] Irritable bowel syndrome (IBS) is a common functional gastrointestinal disease characterized by persistent or intermittent attacks. Its main symptoms are recurrent abdominal pain related to defecation and changes in bowel habits. The prevalence of IBS in most regions is about 5-10%, and the prevalence in China is as high as 7.4%. The prevalence in China has also continued to rise in recent years. As a long-term chronic disease, its symptoms greatly affect the patient's quality of life and social function, and increase the burden on the family and society.

[0003] The clinical manifestations of irritable bowel syndrome are diverse, including abdominal pain, diarrhea, constipation, flatulence, etc., and there is a lack of specific signs and examination indicators, so diagnosis is very difficult. At the same time, its treatment methods are also relatively limited. Although there are some drug and non-drug treatment methods, such as changing dietary habits, drug therapy and psychotherapy, there are great differences in the treatment effects for patients with different symptom types. Since the pathogenesis of irritable bowel syndrome involves multiple aspects such as abnormal intestinal motility, intestinal flora imbalance, mental stress, and increased intestinal sensitivity, its specific pathogenic factors and interactions are still not fully understood. As a complex and diverse disease, irritable bowel syndrome faces many challenges in diagnosis, treatment and scientific research. Therefore, in-depth research on the pathogenesis of irritable bowel syndrome, finding diagnostic indicators, and exploring therapeutic targets are crucial for a comprehensive understanding of irritable bowel syndrome and improving the efficiency of diagnosis and treatment. The study of irritable bowel syndrome requires the construction of an animal model that can accurately reflect the characteristics of human irritable bowel syndrome, which requires overcoming the differences in intestinal physiology between animals and humans and the problems of repeatability and stability of the model.

[0004] The pathogenesis of irritable bowel syndrome is very complex, so it is extremely challenging to construct an animal model that can fully simulate these complex factors. The construction of the mouse irritable bowel syndrome model needs to effectively simulate its complex pathophysiological mechanisms and ensure that the model can stably replicate specific clinical manifestations, such as abdominal pain, diarrhea or constipation, rather than relying solely on the random appearance of symptoms. The currently recognized chronic restraint-induced irritable bowel syndrome model has a long cycle, complex operation, and large individual differences in mice. Therefore, it is urgent to explore new, more direct and simpler ways to induce irritable bowel models. At present, there are no reports showing the role of Lactobacillus murinus in the induction of mouse irritable bowel syndrome models. Summary of the invention

[0005] In view of the problems existing in the prior art, the purpose of the present invention is to provide a method for constructing a mouse irritable bowel syndrome model induced by Lactobacillus murinus. The method uses Lactobacillus murinus as the inducing bacteria of the mouse irritable bowel syndrome model, can quickly and stably replicate the clinical manifestations of irritable bowel syndrome, including visceral sensitivity, colon transit speed and defecation volume, etc., and can be used for subsequent research on irritable bowel syndrome.

[0006] To achieve the above objectives, the present invention provides the following technical solutions:

[0007] A method for constructing a mouse irritable bowel syndrome model induced by Lactobacillus murine. The method establishes the mouse irritable bowel syndrome model by administering a certain amount of Lactobacillus murine to the mouse.

[0008] Preferably, the irritable bowel syndrome is diarrhea-predominant irritable bowel syndrome.

[0009] Preferably, the method comprises administering Lactobacillus murinus by oral administration.

[0010] Preferably, the dosage of Lactobacillus murinus is 1×10 8 ~3×10 8 CFU / mouse, completed in 2 to 3 times within 7 days.

[0011] The beneficial effects of the present invention are:

[0012] The present invention utilizes Lactobacillus rat to conveniently and quickly construct a mouse irritable bowel syndrome model, provides a new use of Lactobacillus rat, and effectively assists subsequent research and mechanism analysis on irritable bowel syndrome. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The figure shows the results of using the abdominal withdrawal reflex test score (AWR) to detect the visceral sensitivity of germ-free mice under different pressures (CRD).

[0014] Figure 2 The figure shows the results of using the abdominal withdrawal reflex test score (AWR) to detect the visceral sensitivity of wild mice under different pressures (CRD).

[0015] Figure 3 This is the result graph of the amount of defecation per unit time of mice.

[0016] Figure 4 This is a graph showing the results of a phenol red excretion experiment to detect the colon propulsion speed of mice. DETAILED DESCRIPTION

[0017] In order to make the technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. If the conditions are not clearly stated in the embodiments, they are carried out under normal conditions, and the instruments or reagents used are all commercially available.

[0018] 1. Experimental Grouping and Experimental Process

[0019] 6-8 weeks old germ-free mice (GF) or wild-type mice (WT) were randomly divided into two groups: ①NT control group: normal diet and water; ②Lactobacillus murinus group (mice were gavaged with Lactobacillus murinus, 2×10 8 CFU / mouse); ③L.brevis group (mice were gavaged with Lactobacillus brevis, 2×10 8 CFU / mouse); ④L. casei group (mice were gavaged with Lactobacillus casei, 2×10 8 CFU / mouse). The animals were gavaged three times (once every two days), and the irritable bowel syndrome-related indicators were tested seven days later. All experimental operations were in accordance with the requirements of the "Guidelines for the Management and Use of Laboratory Animals".

[0020] 2. Observation indicators and methods

[0021] The judgment indicators are the mouse visceral sensitivity, defecation volume per unit time and colon transmission speed.

[0022] The colonic transit speed of mice was tested by the phenol red excretion experiment: the mice were fasted for 24 hours but not water deprived, and then gavaged with 200 microliters of 0.05% phenol red solution (phenol red dissolved in 1.5% carboxymethyl cellulose solution). Then the mice were given food, and feces were collected every 15 minutes and placed in 1 ml of 0.1N sodium hydroxide solution, and the time when phenol red first appeared in the feces of each mouse was recorded.

[0023] The steps of visceral sensitivity detection are as follows: the detection device is mainly composed of a polyethylene balloon (length: 1 cm; diameter: 0.7 cm) connected to a three-way valve through a catheter, and then the balloon catheter is connected to a pressure gauge and a syringe through a three-way valve. During the experiment, the balloon is inflated by injecting gas with a syringe to apply pressure to give the mouse rectum an expansion pressure, and the pressure value is observed by the pressure gauge. During the experiment, we lubricated the balloon with glycerin and inserted it into the mouse rectum. The proximal end of the balloon was about 2 cm away from the anus. The catheter connected to the balloon was fixed to the tail of the mouse rectum with a tape, and the mouse was allowed to fully adapt for 4-5 minutes. The operator injected gas into the balloon at a uniform speed, and the pressure reached 20, 40, 60, and 80 mmHg, respectively, for 20 seconds, and repeated 3 times, each time with an interval of 4-5 minutes. The observer independently and synchronously observed the abdominal withdrawl reflex (AWR) and recorded the score without knowing the inflation pressure and the mouse group. The AWR score is used to evaluate the visceral sensitivity of mice. (AWR scoring criteria: 0 points: no response to expansion; 1 point: only slight head movement; 2 points: abdominal contraction and tremor; 3 points: abdominal lifting; 4 points: abdominal lifting, pelvic lifting, and body bending in an arched shape).

[0024] 3. Experimental results

[0025] The results are as follows Figure 1-3 As shown, germ-free mice (GF) were treated with L.murinus by gavage, or other Lactobacillus species, L.brevis and L.casei. The results showed that only L.murinus could specifically induce visceral hypersensitivity in mice ( Figure 1 ).

[0026] When wild-type mice (WT) were given the same treatment, only L. murinus could directly induce visceral hypersensitivity in mice ( Figure 2 ).

[0027] At the same time, the defecation volume per unit time and colon propulsion speed of the mice in the L.murinus group were significantly faster than those in the control group ( Figure 3-4 ). This further indicates that L. murinus can directly induce irritable bowel syndrome in mice.

[0028] In summary, using Lactobacillus murinus as the inducing bacteria of the mouse irritable bowel syndrome model can quickly and stably replicate the clinical manifestations of diarrhea-predominant irritable bowel syndrome, including visceral sensitivity, colon transit speed and stool volume.

[0029] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for constructing a mouse irritable bowel syndrome model induced by Lactobacillus murineus, characterized in that: This method establishes a mouse irritable bowel syndrome model by administering a certain amount of Lactobacillus murine to mice.

2. The construction method according to claim 1, characterized in that: The irritable bowel syndrome is diarrhea-type irritable bowel syndrome.

3. The construction method according to claim 1, characterized in that: This method administers Lactobacillus murinus by oral administration.

4. The construction method according to claim 1, characterized in that: The dosage of Lactobacillus murinus is 1×10 8 ~3×10 8 CFU / mouse, completed in 2 to 3 times within 7 days.

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