Application of metabolite Neuromedin N to depression-like behavior induced by lipopolysaccharide (LPS)

Abstract

The invention discloses application of a metabolite Neuromedin N to depression-like behaviors induced by lipopolysaccharide (LPS), relates to the technical field of biological medicines, and is technically characterized in that the Neuromedin N can improve the depression-like behaviors induced by the LPS.

Description

Technical Field

[0001] The present invention relates to the field of biomedical technologies, and specifically to the application of metabolite Neuromedin N in lipopolysaccharide (LPS)-induced depressive-like behaviors. Background Art

[0002] Depressive-like behaviors refer to a series of manifestations and symptoms related to depression, but do not necessarily originate from clinically diagnosed depression. These behaviors usually appear in animal models or specific scenarios for studying the pathological mechanisms of depression and the therapeutic effects of drugs. The main manifestations of depressive-like behaviors include social isolation (individuals reducing or avoiding social interactions), decreased activity (lack of interest or motivation, manifested as laziness or idleness), increased stress response (excessive response to common stressors, with large mood swings), and low mood or lack of pleasure (lack of interest or pleasure in daily activities).

[0003] Research has shown that the gut microbiota and its gut metabolites affect brain function through the gut-brain axis and can regulate mood and behavior. Diet is a key environmental factor for regulating the gut microbiota and its metabolites. Spicy foods are very common in people's diets and can improve mood and cognitive function, but due to their irritancy and the complexity of their action mechanisms, they are hindered from being directly applied to the prevention and treatment of diseases such as depression.

[0004] Therefore, the present invention aims to provide the application of metabolite Neuromedin N in LPS-induced depressive-like behaviors to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to solve the above problems and provide the application of metabolite Neuromedin N in LPS-induced depressive-like behaviors. Neuromedin N can improve LPS-induced depressive-like behaviors.

[0006] To achieve the above purpose, the technical solution of the present invention is as follows:

[0007] The present invention provides the application of metabolite Neuromedin N in LPS-induced depressive-like behaviors. The Neuromedin N can be used to prepare drugs for treating LPS-induced depressive-like behaviors.

[0008] Neuromedin N can effectively inhibit LPS-induced apoptosis and inflammatory responses and improve LPS-induced depressive-like behaviors.

[0009] Compared with the prior art, the beneficial effects of this solution:

[0010] The present invention shows that Neuromedin N can improve LPS-induced depressive-like behaviors and can be used to prepare a drug for treating LPS-induced depressive-like behaviors, providing a new idea for curing depressive-like behaviors. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a statistical chart of the number of standing times, the number of grid crossings, the movement distance, the residence time in the open arm, the movement distance in the open arm, and the immobility time of mice after injecting Neuromedin N in the examples of the present invention;

[0012] Figure 2 It is a statistical chart of the number of standing times, the number of grid crossings, the movement distance, the residence time in the open arm, the movement distance in the open arm, and the immobility time of three groups of mice in the examples of the present invention (control group, model group, and drug administration group);

[0013] Figure 3 It is a schematic diagram of Western blot analysis in the examples of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be further described in detail below in conjunction with the embodiments and drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0015] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0016] Example 1:

[0017] An experiment was conducted using mice as experimental subjects

[0018] 1. Metabolite injection

[0019] The mice were evenly divided into an experimental group, a control group 1, a control group 2, a model group, and a drug administration group. The mice in the experimental group were intraperitoneally injected with 0.5 mg / kg Neuromedin N, and the mice in the control group 1 were intraperitoneally injected with 0.5 mg / kg normal saline.

[0020] The mice in the model group and the drug administration group were intraperitoneally injected with an equal amount of LPS, and the control group 2 was injected with an equal amount of normal saline. 24 hours after the LPS injection, the mice in the drug administration group were intraperitoneally injected with Neuromedin N equal to the amount of LPS, and the control group 2 and the model group were intraperitoneally injected with an equal amount of normal saline.

[0021] 2. Construction of a mouse model of depressive-like behavior

[0022] A mouse model of depressive-like behavior was constructed by injecting lipopolysaccharide (LPS) at a dose of. After 24 hours of injection, depressive-like behaviors were observed in the mice, including a significant decrease in the number of standing times in the open field test, a significant decrease in the residence time in the open arms of the elevated plus maze, an increase in the residence time in the closed arms, and a significant increase in the immobility time in the forced swimming test.

[0023] 3. Mouse behavioral experiments

[0024] Open field test: The device is a box of 50×50×40 cm, and the bottom is divided into 9 areas. During the test, the mice perform locomotor and exploratory activities under bright indoor lighting. The mice are placed in the center of the floor, and their activities are videotaped from the top for 5 minutes. During the experiment, the environment is kept quiet, and the researchers avoid making sounds to interfere with the mice's activities. At the end of each experiment, the box is thoroughly cleaned with 75% ethanol. The number of standing times, the number of grid crossings, the distance and duration of staying in each area, and the total locomotor distance are recorded and analyzed using software.

[0025] Elevated plus maze test: The device is divided into 5 areas: 2 open arms, 2 closed arms, and 1 central area; the 2 open arms and 2 closed arms (30×5×15 cm) are connected by 1 central platform (10×10 cm). The device is 50 cm above the ground. The test is carried out in a quiet and dimly lit environment. The mice are placed in the central area with their heads facing the open arms and allowed to freely explore for 5 minutes. A mouse is considered to have entered a new area only when the root of its tail enters. After each mouse's experiment, the device is cleaned with 75% ethanol and dried. The experiment is videotaped throughout the process. The activity time and distance of the mice in the 5 areas are recorded, and animal behavior analysis software is used to track the movement trajectories of the animals and automatically calculate the indexes.

[0026] Forced swimming test: The device is a transparent cylinder with a diameter of 20 cm and a height of 50 cm, containing about 30 cm deep water, and the experiment is carried out at room temperature. At the start of the experiment, the researchers put the mice into the cylinder and immediately leave the room to avoid human interference, and the test lasts for 5 minutes. After the experiment, the mice are fished out of the water, dried, and then put back into the cage. All the test swimming processes are videotaped and analyzed using animal behavior analysis software. Immobility refers to the time when the mice remain stationary during the test. When the motion of the mice <0.06, the software determines it as immobile.

[0027] Morris water maze test: The device includes 1 circular pool (diameter 120 cm, height 45 cm) and 1 escape platform with a diameter of 9 cm, and 4 markers with different shapes and colors are pasted on the pool wall. The whole test is divided into 3 stages: pre-training experiment (2 days), place navigation experiment (5 days), and spatial exploration experiment (1 day).

[0028] During the pre-training experiment, the water level was below the top of the escape platform at room temperature. Mice were placed into the pool in different quadrant orders. If a mouse did not find the platform within 60 s, it was guided to the platform and stayed on the platform for no less than 15 s. After completion, the mouse was dried with a towel.

[0029] During the place navigation experiment, the water surface was raised to 1 cm above the platform. Titanium dioxide was added and stirred to make the platform invisible, and the mice were placed into the pool from the markers at different quadrants. The swimming time limit for each mouse was 60 s. If a mouse found the circular platform and climbed onto the platform within the specified time, the time taken by the mouse from entering the water to climbing onto the platform was recorded as its "escape latency". If a mouse did not find the platform within the 60-s time limit, the researchers would guide them onto the platform and let them stay for 15 s, and the "escape latency" at this time was 60 s. The mice were randomly placed in one of the 4 wall cues facing the pool. The test was conducted 2 times a day, with an interval of about 2 h each time.

[0030] For the spatial exploration experiment, the platform was removed and the mice were placed into the pool. The number of times the mice crossed the original platform area within 60 s and the swimming time and distance in the 4 quadrants were recorded. The whole experiment was videotaped, and the software automatically recorded the swimming speed of the mice.

[0031] 4. Statistical methods

[0032] The experimental data were statistically analyzed for two groups of data using SPSS 21.0 software. The independent sample T-test was used to compare the means, and the results were expressed as mean ± standard deviation (SD). The significance level was set at P < 0.05. Origin 2010 software was used for graphing.

[0033] 5. Experimental results

[0034] 5.1 Effects of metabolite Neuromedin N on the behavior of normal mice

[0035] The mice in the experimental group were intraperitoneally injected with Neuromedin N, and the mice in control group 1 were intraperitoneally injected with an equal amount of normal saline. After 4 h, the open field test, elevated plus maze test, and forced swimming test were conducted. Figure 1 It can be seen that compared with normal mice, the number of standing times of the mice in the experimental group in the open field was significantly increased, and the staying time and moving distance in the open arms of the elevated plus maze were significantly increased.

[0036] 5.2 Effects of metabolite Neuromedin N on mice with lipopolysaccharide (LPS)-induced depressive-like behavior

[0037] The mice in the model group and the drug administration group were intraperitoneally injected with an equal amount of LPS, aiming to induce depressive-like behaviors in the mice. The second control group was injected with an equal amount of normal saline. 24 hours after the LPS injection, the mice in the drug administration group were intraperitoneally injected with an equal amount of Neuromedin N as that of LPS, and the second control group and the model group were intraperitoneally injected with an equal amount of normal saline. Behavioral experiments were conducted 4 hours later. The results are as Figure 2 shown. Compared with the second control group, the mice injected with LPS significantly showed depressive-like behaviors, and the number of standing times, the number of grid crossings, and the movement distance in the open field test were extremely significantly reduced, indicating that the depressive model was successfully constructed. Compared with the control group, there were significant differences in the number of standing times and the movement distance in the open field of the drug administration group, while there was no significant difference in the number of grid crossings. The number of standing times, the number of grid crossings, and the movement distance in the open field were significantly increased compared with the model group. The data showed that there were no significant differences in the immobility time of forced swimming and the residence time in the open arms of the elevated plus maze test between the model group and the second control group, so it was not statistically significant. There were also no significant differences in the immobility time of forced swimming and the residence time in the open arms of the elevated plus maze test in the drug administration group. Based on the results of the open field test, it can be confirmed that Neuromedin N can improve the depressive-like behaviors induced by LPS in mice.

[0038] Example 2:

[0039] The LPS-induced depressive model is through activating microglial cell inflammation and apoptosis. The anti-depressant effect of Neuromedin N was verified by using the brain-derived microglial cell line BV2 to determine whether it is through inhibiting glial cell inflammation and apoptosis. The cultured BV2 cells were co-treated with 10 μg / mL of Neuromedin N and 100 μM of LPS, and three groups were set up: the control group (CTL), the LPS treatment group (LPS), and the LPS+Neuromedin N co-treatment group (NN). After 12 hours of treatment, the cells were collected to extract proteins, and the expression levels of apoptosis-related factors (BAX, BCL2) and inflammation-related factors (IL6, IL-1β) were analyzed by Western blot.

[0040] The representative Western blot results are as Figure 3 shown. The bar graph is the average value of three experiments (mean±SEM), and one-way ANOVA was used for statistical analysis. *p<0.05 indicates significant difference, **p<0.01 indicates very significant difference, and ***p<0.001 indicates extremely significant difference.

[0041] The above results indicate that Neuromedin N can effectively inhibit the cell apoptosis and inflammatory response induced by LPS, which is one of the mechanisms of the anti-depressant effect of Neuromedin N.

[0042] The above specific embodiments are only explanations of the present invention, and they are not limitations on the present invention. After reading this specification, those skilled in the art can make modifications to these embodiments that do not contribute creatively as needed, but as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. Application of metabolite Neuromedin N in lipopolysaccharide (LPS)-induced depressive-like behaviors, characterized by: The Neuromedin N can be used to prepare a drug for treating LPS-induced depressive-like behavior.

2. Use of metabolite Neuromedin N in lipopolysaccharide (LPS)-induced depressive-like behaviors, characterized in that: The Neuromedin N can effectively inhibit LPS-induced apoptosis and inflammatory response and improve LPS-induced depressive-like behavior.

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