Application of opioid receptor stimulant in preparation of medicine for treating Alzheimer disease

Abstract

The invention discloses an application of an opioid receptor stimulant in preparation of a medicine for treating Alzheimer disease. Wherein the opioid receptor stimulant can activate the phagocytic function of astrocytes and enhance the A beta plaque phagocytic ability of the astrocytes, so that the astrocytes play a greater role in A beta plaque removal, and the A beta plaque accumulation of amyloid protein can be remarkably reduced. Therefore, the opioid receptor stimulant can be applied to preparation of the medicine for treating the Alzheimer disease. Meanwhile, the opioid receptor stimulant can effectively improve the cognitive function. In addition, experiments prove that the opioid receptor stimulant has good safety and tolerance when being used as a medicine for treating the Alzheimer disease.

Description

Technical Field

[0001] The present invention relates to a new use of an opioid receptor agonist, in particular to the use of an opioid receptor agonist in preparing a drug for treating Alzheimer's disease, and belongs to the field of medical technology. Background Art

[0002] Alzheimer's disease (AD) is a common degenerative disease in the elderly, the main feature of which is the gradual decline of cognitive function. With the acceleration of population aging, the number of AD patients is increasing. AD not only causes great pain to the patients themselves, but also has a high disability rate. Patients often lose the ability to live independently in the late stage. It also brings heavy economic and nursing burdens to society and families, becoming one of the major diseases that seriously affects the health of the elderly and China's sustainable development. Therefore, exploring effective AD treatment methods is an important health and social challenge currently faced.

[0003] In the treatment research of AD, the development of drugs targeting β-amylo id (Aβ) has made some progress. These drugs mainly slow down the progression of the disease by reducing the accumulation of Aβ, promoting its clearance or inhibiting its aggregation. For example, Aducanumab is an approved monoclonal antibody drug that can reduce Aβ plaques in the brain. However, this type of therapy has challenges in practical application, such as requiring high doses to achieve therapeutic effects and may cause side effects such as brain inflammation. In addition, small molecule drugs such as PBT 1 and PBT2, which prevent Aβ aggregation by binding to metal ions, have not significantly improved patients' cognitive function in clinical trials, although they have shown potential in preclinical studies. BACE-1 inhibitors work by reducing the production of Aβ. Although they have theoretical potential, multiple BACE-1 inhibitors have been terminated in clinical trials due to severe side effects and insufficient efficacy.

[0004] Opioid receptor agonists are a class of drugs used clinically to treat diseases such as pain. They work by activating opioid receptors. This class of drugs includes μ opioid receptor agonists, δ opioid receptor agonists, and κ opioid receptor agonists. Morphine and its derivatives, such as morphine hydrochloride, are the main drugs used to relieve severe pain. Although opioid receptor agonists are widely used in pain treatment, there have been no reports of using opioid receptor agonists such as morphine to treat AD. Summary of the invention

[0005] The primary technical problem to be solved by the present invention is to provide a new use of an opioid receptor agonist, mainly providing an use of an opioid receptor agonist in the preparation of a drug for treating Alzheimer's disease.

[0006] Another technical problem to be solved by the present invention is to provide an application of an opioid receptor agonist in the preparation of a drug for treating the deposition or accumulation of amyloid protein Aβ.

[0007] Another technical problem to be solved by the present invention is to provide an application of an opioid receptor agonist in the preparation of a drug for clearing / reducing amyloid protein Aβ.

[0008] Another technical problem to be solved by the present invention is to provide an application of an opioid receptor agonist in the preparation of a drug for improving / treating cognitive dysfunction.

[0009] Preferably, the Alzheimer's disease is associated with the deposition of amyloid protein Aβ.

[0010] Preferably, the drug promotes the clearance of the amyloid protein Aβ by affecting the amyloid protein Aβ phagocytic ability of astrocytes; and / or,

[0011] The drug reduces the accumulation of amyloid Aβ; and / or,

[0012] The medicament can improve cognitive dysfunction (eg, cognitive dysfunction caused by Alzheimer's disease).

[0013] Preferably, in the drug, the effective dose of the opioid receptor agonist is 0.5-50 mg / Kg, preferably 1-20 mg / Kg; more preferably 8-15 mg / Kg, for example 8 mg / Kg, 9 mg / Kg, 10 mg / Kg, 11 mg / Kg or 12 mg / Kg.

[0014] Preferably, the drug is in the form of an oral dosage form, an injection, or a suppository, preferably an injection; wherein the oral dosage form is preferably a tablet, an oral solution, or a sustained-release dosage form, such as a sustained-release tablet or a sustained-release capsule.

[0015] Preferably, an effective dose of 5 to 30 mg / Kg (e.g., 8, 9, 10, 11, 12 mg / Kg) of opioid receptor agonist is administered daily for 5 to 14 days (preferably 6 to 10 days, e.g., 8 days); preferably, the administration method is injection; preferably, the effective dose is administered 1 to 3 times a day, more preferably once a day.

[0016] Preferably, the effective daily dosage of the tablet is 15 to 100 mg (e.g., 15 to 60 mg), and each administration is 5 to 30 mg (e.g., 5 to 15 mg); and / or,

[0017] The effective daily dosage of the oral solution is 15 to 100 mg (e.g., 15 to 60 mg), and each administration is 5 to 30 mg (e.g., 5 to 15 mg); and / or,

[0018] The effective daily dosage of the sustained-release dosage form is 20 to 50 mg (e.g., 25 to 40 mg), with 10 to 20 mg administered each time; and / or,

[0019] The suppository is a suppository for rectal administration, and the effective daily dosage is 10 to 100 mg (eg, 25 to 40 mg), and 5 to 30 mg is administered each time.

[0020] Preferably, the opioid receptor agonist is selected from at least one of a μ opioid receptor agonist, a κ opioid receptor agonist, and a δ opioid receptor agonist;

[0021] Preferably, the μ opioid receptor agonist is selected from at least one of morphine, morphine derivatives (such as morphine hydrochloride), fentanyl, sufentanil, remifentanil, methadone, piperazine and oxycodone.

[0022] Compared with the prior art, the present invention has the following beneficial effects: First, by activating the phagocytic function of astrocytes, the phagocytic ability of astrocytes to amyloid protein Aβ plaques is enhanced, thereby promoting the clearance of Aβ plaques and significantly reducing the accumulation of Aβ plaques in the brain. Secondly, it not only targets the pathological characteristics of AD, but also effectively improves the cognitive dysfunction caused by AD. Through experimental verification, AD model mice treated with opioid receptor agonists showed significant improvement in cognitive function tests, reaching a cognitive level comparable to that of wild-type mice. In addition, the present invention also confirms the good safety and tolerability of opioid receptor agonists in the treatment of AD, providing a new treatment option for AD patients, which has important clinical application value and social significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1a This is a schematic diagram of the subcutaneous injection and sampling of morphine;

[0024] Figure 1b Representative images of immunofluorescence staining using antibody 6E10 that specifically recognizes amyloid plaques;

[0025] Figure 1c The 6E10 positive cells were 5xFAD mice (6E10 positive cells) at 0, 3 and 6 DPI, respectively. + ) of amyloid plaque area fraction;

[0026] Figure 1dThe 6E10 positive cells were 5xFAD mice (6E10 positive cells) at 0, 3 and 6 DPI, respectively. + ) of the amyloid plaque count;

[0027] Figure 2a These are the movement trajectories of mice in the open field test in the WT+sal ine (n=9), WT+morphine (n=9), 5xFAD+sal ine (n=9), and 5xFAD+morphine (n=10) groups;

[0028] Figure 2b The moving distance statistics of WT+saline (n=9), WT+morphine (n=9), 5xFAD+saline (n=9), and 5xFAD+morphine (n=10) groups in the open field test;

[0029] Figure 2c This is a statistical graph of the time that WT+saline (n=8), WT+morphine (n=9), 5xFAD+saline (n=9), and 5xFAD+morphine (n=10) groups stayed in the central area in the open field experiment;

[0030] Figure 2d The movement trajectory of mice in the BM experiment, WT+sal ine (n=8), WT+morphine (n=8), 5xFAD+sal ine (n=10), 5xFAD+morphine (n=10) on the 5th training day and the test day;

[0031] Figure 2e This is a statistical chart of the time it takes for the WT+saline (n=8), WT+morphine (n=8), 5xFAD+saline (n=10), and 5xFAD+morphine (n=10) groups to find the target hole during the training phase of the BM experiment;

[0032] Figure 2f This is a statistical chart of the time it takes for each group, WT+saline (n=8), WT+morphine (n=8), 5xFAD+saline (n=10), and 5xFAD+morphine (n=10), to find the target hole for the first time during the BM experimental test phase;

[0033] Figure 2gThis is a statistical chart of the time spent at the target hole by the WT+saline (n=8), WT+morphine (n=8), 5xFAD+saline (n=10), and 5xFAD+morphine (n=10) groups during the BM experimental test phase;

[0034] Figure 2h The movement trajectories of mice in the WM experiment on the 5th training and test day for WT+saline (n=8), WT+morphine (n=8), 5xFAD+saline (n=8), and 5xFAD+morphine (n=9);

[0035] Figure 2i This is a statistical chart of the time it takes for the WT+saline (n=8), WT+morphine (n=8), 5xFAD+saline (n=8), and 5xFAD+morphine (n=9) groups to find the target hole during the training phase of the WM experiment;

[0036] Figure 2j This is a statistical chart of the time it takes for each group, WT+saline (n=8), WT+morphine (n=8), 5xFAD+saline (n=8), and 5xFAD+morphine (n=9), to find the target hole for the first time during the WM experimental test phase;

[0037] Figure 2k This is a statistical chart of the number of times each group of WT+saline (n=8), WT+morphine (n=8), 5xFAD+saline (n=8), and 5xFAD+morphine (n=9) stayed at the target hole during the WM experimental test phase;

[0038] Figure 2l This is a statistical chart of the time spent at the target hole by the WT+saline (n=8), WT+morphine (n=8), 5xFAD+saline (n=8), and 5xFAD+morphine (n=9) groups during the WM experimental test phase;

[0039] Figure 3a The immunofluorescence staining statistics of Iba1-positive microglia, GFAP-positive astrocytes and 6E10-positive plaques in the 5xFAD-saline (n=6) and 5xFAD-morphine (n=6) groups;

[0040] Figure 3b The numbers of GFAP-positive astrocytes around the plaques in the 5xFAD-saline (n=6) and 5xFAD-morphine (n=6) groups were counted;

[0041] Figure 3c The numbers of Iba1-positive microglia around plaques in the 5xFAD-saline (n=6) and 5xFAD-morphine (n=6) groups were counted;

[0042] Figure 3d The figures are the percentage of the volume of the plaque engulfed by Iba1-positive microglia to the total volume of the plaque in the 5xFAD-saline (n=6) and 5xFAD-morphine (n=6) groups;

[0043] Figure 3e The figures are the statistics of the ratio of the volume of the plaques engulfed by GFAP-positive astrocytes to the total volume of the plaques in the 5xFAD-saline (n=6) and 5xFAD-morphine (n=6) groups. DETAILED DESCRIPTION

[0044] The technical content of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0045] In order to better understand the present invention, definitions and explanations of relevant terms are provided below.

[0046] "Opioid receptor agonists" are drugs that exert analgesic effects by stimulating μ, κ and δ opioid receptors in the peripheral and central nervous systems, including μ opioid receptor agonists, δ opioid receptor agonists, κ opioid receptor agonists, etc. The opioid receptor agonists suitable for the present invention are preferably μ opioid receptor agonists, including but not limited to: morphine, morphine derivatives (such as morphine hydrochloride), fentanyl, sufentanil, remifentanil, methadone, piperazine and oxycodone.

[0047] "Effective dose" refers to the dose at which the drug begins to show its efficacy. In the present invention, although the maximum or limit dose is sometimes not mentioned or limited, those skilled in the art should understand that the "effective dose" should be lower than the limit dose for safe medication. In the present invention, the effective dose of the opioid receptor agonist is 0.5-50 mg / Kg; preferably 1-20 mg / Kg, more preferably 8-15 mg / Kg, for example 8 mg / Kg, 9 mg / Kg, 10 mg / Kg, 11 mg / Kg or 12 mg / Kg, etc.

[0048] "Dosage form" refers to the form of drug application prepared by making the drug into a certain shape according to the characteristics of the disease and the drug to meet the needs of treatment or prevention. In the present invention, opioid receptor agonists can be formulated into oral preparations, injections, sustained-release dosage forms (such as sustained-release tablets or sustained-release capsules), suppositories, etc. as drugs for the treatment of Alzheimer's disease, preferably injections. The injection method can be subcutaneous injection, intramuscular injection, intravenous injection, epidural injection, subarachnoid injection, etc. In some embodiments of the present invention, the drug is an injection, preferably subcutaneous or intravenous injection. In a preferred embodiment, the drug containing an effective dose (such as 10 mg / Kg) of an opioid receptor agonist is injected once a day for 8 consecutive days.

[0049] "6E10" is an antibody that is mainly used to detect abnormal accumulation of proteins. It is a monoclonal antibody against beta-amyloid protein (Aβ), which can recognize and bind to Aβ protein for research and analysis. In Alzheimer's disease research, 6E 10 is widely used to detect the deposition of Aβ protein. In the present invention, 6E10 is used to detect the area and number of Aβ protein plaques in 5xFAD mice.

[0050] "6E10 + " indicates a 6E10 positive signal. In the present invention, 6E10 + The marked position represents where Aβ protein is detected, and this method is used to determine the Aβ protein plaque area, plaque number, etc.

[0051] "DPI" is the abbreviation of day post injection, which means the condition (e.g., number of days) after injection. In the present invention, it means testing 5xFAD mice after treatment or injection. For example, 3DPI refers to testing 5xFAD mice after continuous injection of morphine for 3 days.

[0052] "Astrocytes" are the most widely distributed type of cells in the mammalian brain and are also the largest type of glial cells. Such glial cells are star-shaped, stretching and filling between the cell bodies and processes of nerve cells, supporting and separating nerve cells, and participating in the formation of the blood-brain barrier. In the present invention, astrocytes engulf and clean up Aβ deposits in brain tissue in a receptor-mediated manner, thereby reducing the toxic effects of Aβ. It is well known to those skilled in the art that "GFAP (Glyal Fibrillary Acid Protein)" is a marker for astrocytes.

[0053] "Microglia" is a type of glial cell, accounting for about 10% to 15% of glial cells in the brain, which is equivalent to macrophages residing in the brain and spinal cord. Currently known functions of microglia include clearance, phagocytosis, antigen presentation, synaptic stripping, promotion of damage repair and secretion of extracellular signals, etc. They play an important role in physiological and pathological processes such as neural development, brain tissue maintenance, synaptic remodeling, neuroinflammation, brain infection, cytotoxicity and neurodegenerative diseases. In the present invention, microglia play the role of engulfing the amyloid protein Aβ related to Alzheimer's disease. It is well known to those skilled in the art that "lba1" is a marker for microglia.

[0054] "5xFAD mice" are a transgenic mouse model used to study and simulate Alzheimer's disease (AD). These mice are genetically designed to rapidly accumulate Aβ plaques and are a common model for studying AD pathology. In the present invention, they are used as experimental subjects in the embodiments of the present invention.

[0055] "WT (wild type) mice" refers to wild type mice. In the present invention, wild type mice are used as experimental subjects in the examples and compared with 5xFAD mice.

[0056] "BM" is the abbreviation of Barnes Maze, which means Barnes maze experiment, which is used to evaluate the cognitive ability of experimental mice.

[0057] "WM" is the abbreviation of Water Maze, which means water maze experiment, which is used to evaluate the cognitive ability of experimental mice.

[0058] One aspect of an embodiment of the present invention provides a new use of an opioid receptor agonist, that is, a new use of an opioid receptor agonist in the preparation of a drug for treating Alzheimer's disease.

[0059] According to the above new uses, opioid receptor agonists can effectively treat AD, improve the phagocytic function of astrocytes on amyloid Aβ, promote the clearance of amyloid Aβ, reduce the accumulation of amyloid Aβ plaques in the brain, significantly improve cognitive function, and have good safety and tolerability.

[0060] Therefore, another aspect of the embodiments of the present invention relates to the use of an opioid receptor agonist in the preparation of a medicament for treating the deposition or accumulation of amyloid protein Aβ.

[0061] In addition, the present invention also relates to the use of an opioid receptor agonist in preparing a drug for improving / treating cognitive dysfunction.

[0062] One embodiment of the present invention relates to the use of an opioid receptor agonist in the preparation of a drug for treating Alzheimer's disease. Preferably, the Alzheimer's disease is Alzheimer's disease associated with amyloid Aβ deposition.

[0063] Drugs containing opioid receptor agonists can promote the clearance of amyloid Aβ by affecting the phagocytic ability of astrocytes to engulf amyloid Aβ. Further, the drug can reduce the accumulation of amyloid Aβ. Further, the drug can improve cognitive dysfunction (e.g., cognitive dysfunction caused by Alzheimer's disease).

[0064] Another aspect of the embodiments of the present invention relates to the use of opioid receptor agonists in the preparation of drugs for removing / reducing amyloid Aβ. In some embodiments, the present invention enhances the amyloid Aβ phagocytic ability of astrocytes and promotes the removal of amyloid Aβ. In a specific embodiment, when morphine is injected subcutaneously at an effective dose of 10 mg / Kg for 8 consecutive days, the phagocytic ability of astrocytes in the brain of 12-month-old 5xFAD mice is enhanced, promoting the removal of the amyloid Aβ.

[0065] Another aspect of the embodiments of the present invention relates to the use of opioid receptor agonists in the preparation of drugs for treating amyloid Aβ deposition or accumulation. In some embodiments, the present invention significantly reduces the accumulation of amyloid Aβ plaques. When morphine is injected subcutaneously at an effective dose of 10 mg / Kg for 8 consecutive days, the level of amyloid Aβ plaques in the brain of 12-month-old 5xFAD mice is reduced by 80%. Compared with the 5% improvement of amyloid Aβ plaques by Aducanumab monoclonal antibody under the same treatment regimen, this significant reduction indicates that opioid receptor agonists, such as morphine, have a strong efficacy in clearing Aβ plaques.

[0066] Another aspect of the embodiments of the present invention relates to the use of opioid receptor agonists in the preparation of drugs for improving / treating cognitive dysfunction. In some embodiments, the present invention effectively improves cognitive dysfunction caused by Alzheimer's disease. When morphine is injected subcutaneously at an effective dose of 10 mg / Kg for 8 consecutive days, 12-month-old 5xFAD mice show significant improvement in cognitive ability in the Barnes maze test, reaching a level comparable to that of wild-type mice, substantially improving the cognitive function of AD model mice.

[0067] In some embodiments, the effective dose of the opioid receptor agonist in the drug is 0.5 to 50 mg / Kg; preferably 1 to 20 mg / Kg, and more preferably 8 to 15 mg / Kg, such as 8 mg / Kg, 9 mg / Kg, 10 mg / Kg, 11 mg / Kg or 12 mg / Kg. In some embodiments, the drug preparation dosage form is any one of an oral dosage form, an injection, and a suppository, preferably an injection. The oral dosage form is any one of a tablet, an oral liquid, a sustained-release dosage form (such as a sustained-release tablet, a sustained-release capsule), etc. The administration method of the injection can be subcutaneous injection, intramuscular injection, intravenous injection, epidural injection, subarachnoid injection, etc., preferably subcutaneous injection or intravenous injection. The administration method of the suppository is preferably rectal administration.

[0068] In some embodiments, an effective dose (eg, 5-20 mg / Kg) of an opioid receptor agonist is administered daily for 5-14 days, preferably 6-10 days, such as 8 or 9 days. In a specific embodiment, the administration is by injection.

[0069] In some embodiments, the effective dose is administered 1 to 3 times a day, more preferably once a day.

[0070] In a specific embodiment, the drug containing an effective dose (eg, 10 mg / Kg) of the opioid receptor agonist is injected daily for 8 consecutive days.

[0071] In some embodiments, other dosage forms and administration methods may also be used, such as oral administration or suppositories.

[0072] The effective daily dose of the tablet is 15 to 100 mg (e.g., 15 to 60 mg), and 5 to 30 mg (e.g., 5 to 15 mg) is administered each time. In the case of an oral solution, the effective daily dose is 15 to 100 mg (e.g., 15 to 60 mg), and 5 to 30 mg (e.g., 5 to 15 mg) is administered each time. In the case of a sustained-release dosage form, the effective daily dose is 20 to 50 mg (e.g., 25 to 40 mg), and 10 to 20 mg is administered each time. Suppositories are preferably rectal suppositories, and the effective daily dose is 10 to 100 mg (e.g., 25 to 40 mg), and 5 to 30 mg is administered each time.

[0073] In the above embodiment, the opioid receptor agonist is selected from at least one of μ opioid receptor agonists, κ opioid receptor agonists, δ opioid receptor agonists, etc. Preferably, the μ opioid receptor agonist is selected from at least one of morphine, morphine derivatives (such as morphine hydrochloride), fentanyl, sufentanil, remifentanil, methadone, piperazine and oxycodone.

[0074] Example

[0075] The technical scheme described herein will be more easily understood by reference to the following examples, which are provided by way of illustration and are not intended to limit the present invention. In addition, the experimental methods in the following examples are conventional methods unless otherwise specified. The raw materials, reagent materials, etc. used in the following examples are all commercially available products unless otherwise specified.

[0076] Embodiment 1:

[0077] Example 1 is an experiment based on the level of Aβ plaques in the mouse brain.

[0078] Twelve 12-month-old 5xFAD mice were randomly divided into two groups, 6 mice in each group, a blank control group and a morphine injection group. One group was given 10 mg / kg of morphine per day by subcutaneous injection, and the other group was injected with the same dose of saline solution as a blank control test for 8 consecutive days.

[0079] After the treatment, the 5xFAD mice were tested. The Aβ plaque levels in the mouse brain were detected by immunohistochemistry. Figure 1a to Figure 1d As shown, Figure 1a This is a schematic diagram of the subcutaneous injection of morphine and the sampling plan. Figure 1b This is a representative image of immunofluorescence staining using the antibody 6E10 that specifically recognizes amyloid plaques. It can be seen from the figure that compared with the 5xFAD mouse group injected with normal saline, the level of brain plaques in 12-month-old 5x FAD mice on days 0 (0DPI), 3 (3DPI) and 6 (6DPI) after subcutaneous injection of morphine gradually decreased.

[0080] Figure 1c The 12-month-old 5xFAD mice were 6E10 positive (i.e., 6E10 + ) of the amyloid plaque area fraction of 5xFAD mice. It can be seen from the figure that compared with the injection of saline, the injection of morphine increased the amyloid plaque area fraction of 5xFAD mice 6E10 + The plaque area score was significantly reduced; with the increase of morphine injection days, 5xFAD mice 6E10 + The plaque area score was also gradually decreasing.

[0081] Figure 1d The 12-month-old 5xFAD mice were 6E10 positive (i.e., 6E10 + ) of the 5xFAD mice. It can be seen from the figure that compared with the injection of saline, the number of amyloid plaques in 6E10 mice injected with morphine increased significantly. +The number of plaques decreased significantly; with the increase of morphine injection days, 5xFAD mice 6E 10 + The number of plaques is also gradually decreasing; after 8 consecutive days of morphine treatment, the level of Aβ plaques in the mouse brain was significantly reduced by 80%. The existing literature (The antibody aducanumab reduces Aβ plaques in Alzheimer's disease. Nature, 537, 50-6, 2016) pointed out that Aducanumab monoclonal antibody reduced the level of Aβ plaques in the mouse brain by 5% under the same experimental scheme. Compared with this effect, the significant reduction in Aβ plaques shown in the embodiment of the present invention shows that morphine has a strong effect in clearing Aβ plaques.

[0082] Embodiment 2:

[0083] Example 2 is an experiment based on the cognitive function of mice.

[0084] 12-month-old 5xFAD mice and WT mice matched with them in sex and age were selected. The 5xFAD mice were randomly divided into two groups, each with n≥8 mice, namely, a blank control group (5xFAD+sal ine (normal saline)) and a morphine injection group (5xFAD+morphine (morphine)); WT mice were also randomly divided into two groups, each with n≥8 mice, namely, a blank control group (WT+sal ine (normal saline)) and a morphine injection group (WT+morphine (morphine)). 5xFAD mice and WT mice were treated by subcutaneous injection. One group was given 10 mg / Kg of morphine daily, and the other group was injected with the same dose of normal saline solution as a blank control test, and the injections were continued for 8 days.

[0085] (1) Open field test

[0086] The open field test was used to evaluate the cognitive function of mice. Figure 2a to Figure 2c As shown. Among them, Figure 2a It represents the movement trajectory of mice in WT+saline (n=9), WT+morphine (n=9), 5xFAD+saline (n=9), and 5xFAD+morphine (n=10) groups in the open field test. Figure 2b It represents the statistical graph of movement distance of WT+saline (n=9), WT+morphine (n=9), 5xFAD+saline (n=9), 5xFAD+morphine (n=10) groups in the open field test; Figure 2cThe figure shows the time spent in the central area by WT+saline (n=8), WT+morphine (n=9), 5xFAD+saline (n=9), and 5xFAD+morphine (n=10) groups in the open field test. As can be seen from the figure, the movement distances of the four groups of mice are comparable. When the movement distances are comparable, the time spent in the central area by morphine-injected 5xFAD mice is comparable to that of wild-type mice, indicating that the cognitive function of AD mice is basically restored 8 days after morphine injection.

[0087] (2) Barnes maze test

[0088] The Barnes Maze Test (BM) was used to evaluate the cognitive function of mice. Figure 2d to Figure 2g shown. Figure 2d The figure shows the movement trajectory of mice in the BM experiment, WT+saline (n=8), WT+morphine (n=8), 5xFAD+saline (n=10), and 5xFAD+morphine (n=10) on the 5th training and test day. As can be seen from the figure, the morphine-injected 5xFAD mice can find the target end point in the test during training and the final test, while the saline-injected 5xFAD mice find it difficult to find the target end point in the final test.

[0089] Figure 2e It is the statistical graph of the time it takes for the WT+saline (n=8), WT+morphine (n=8), 5xFAD+saline (n=10), and 5xFAD+morphine (n=10) groups to find the target hole during the training phase of the BM experiment; Figure 2f It is the statistical graph of the time it takes for each group of WT+sal ine (n=8), WT+morphine (n=8), 5xFAD+sal ine (n=10), and 5xFAD+morphine (n=10) to find the target hole for the first time during the BM experimental test phase; Figure 2g The following are the statistical graphs of the time spent at the target hole by WT+saline (n=8), WT+morphine (n=8), 5xFAD+saline (n=8), and 5xFAD+morphine (n=9) groups during the BM test phase. From these graphs, it can be seen that the ability of morphine-injected 5xFAD mice to find the target hole is comparable to that of wild-type mice.

[0090] (3) Water maze experiment

[0091] The water maze test (WM) was used to evaluate the cognitive function of mice. Figure 2h to Figure 2l shown. Figure 2h The figure shows the movement trajectory of mice in the WM experiment on the fifth training and test day for WT+saline (n=8), WT+morphine (n=8), 5xFAD+saline (n=8), and 5xFAD+morphine (n=9). As can be seen from the figure, the morphine-injected 5xFAD mice can find the target endpoint in the test both during training and in the final test, while the saline-injected 5xFAD mice have difficulty finding the target endpoint in the final test.

[0092] Figure 2i It is the statistical graph of the time it takes for the WT+saline (n=8), WT+morphine (n=8), 5xFAD+saline (n=8), and 5xFAD+morphine (n=9) groups to find the target hole during the training phase of the WM experiment; Figure 2j It is a statistical graph of the time it takes for each group of WT+sal ine (n=8), WT+morphine (n=8), 5xFAD+sal ine (n=8), and 5xFAD+morphine (n=9) to find the target hole for the first time during the WM experimental test phase; Figure 2k It is a statistical chart of the number of times each group of WT+sal ine (n=8), WT+morphine (n=8), 5xFAD+sal ine (n=8), and 5xFAD+morphine (n=9) stayed at the target hole during the WM experimental test phase;

[0093] Figure 2l The following are the statistical graphs of the time spent at the target hole by WT+saline (n=8), WT+morphine (n=8), 5xFAD+saline (n=8), and 5xFAD+morphine (n=9) groups during the WM test phase. From these graphs, it can be seen that the ability of morphine-injected 5xFAD mice to find the target hole is comparable to that of wild-type mice.

[0094] Above Figure 2a to Figure 2l The experimental results shown demonstrate that morphine-treated 5xFAD mice performed significantly better on the test, reaching a cognitive level comparable to wild-type mice.

[0095] Embodiment 3:

[0096] Example 3 is an experiment based on the phagocytic function of astrocytes.

[0097] Twelve 12-month-old 5xFAD mice were randomly divided into two groups, 6 mice in each group, namely a blank control group (5xFAD-sal ine) and a morphine injection group (5xFAD-morphine). Subcutaneous injection was used to give 10 mg / Kg of morphine per day in one group, and the same dose of saline was injected as a blank control for 8 consecutive days.

[0098] After the treatment, the plaque-associated glial cells of 5xFAD mice were detected, and the results were as follows Figure 3a to Figure 3e As shown. Among them, Figure 3a The immunofluorescence staining statistics of Iba1-positive microglia, GFAP-positive astrocytes and 6E10-positive plaques in the 5xFAD-sal ine (n=6) and 5xFAD-morphine (n=6) groups. As can be seen from the figure, the plaque area covered by astrocytes in mice injected with morphine is significantly larger than that in mice injected with normal saline, and there is no difference in microglia or the phagocytic area is smaller. These results show that in mice injected with normal saline, microglia mainly perform plaque phagocytosis, and astrocytes surround microglia and plaques, but do not mainly participate in phagocytosis; in the morphine injection group, the aggregation and phagocytosis of microglia are relatively weakened, and the phagocytic function of astrocytes is enhanced. This means that morphine activates the phagocytic function of astrocytes, allowing astrocytes to play a greater role in the clearance of Aβ plaques.

[0099] Figure 3b , Figure 3c is the statistical number of related glial cells around the plaques in the 5xFAD-sal ine and 5xFAD-morphine groups; Figure 3d , Figure 3e The 5xFAD-saline and 5xFAD-morphine groups show the percentage of the volume of the plaque engulfed by glial cells. As can be seen from these figures, there are significantly more astrocytes in the mice injected with morphine than in the mice injected with saline, indicating that morphine treatment significantly enhances the Aβ engulfment ability of astrocytes, thereby promoting the clearance of Aβ plaques.

[0100] In addition, it can be seen from the above results that mice treated with morphine did not show obvious side effects, indicating that this treatment regimen has good safety and tolerability.

[0101] In summary, opioid receptor agonists can activate the phagocytic function of astrocytes, enhance the Aβ plaque phagocytic ability of astrocytes, enable astrocytes to play a greater role in the removal of Aβ plaques (see Example 3 for details), and can significantly reduce the accumulation of amyloid Aβ plaques (see Example 1 for details). Therefore, opioid receptor agonists can be used as an application for preparing drugs for treating Alzheimer's disease. At the same time, opioid receptor agonists can effectively improve cognitive function (see Example 2 for details). In addition, the present invention has experimentally confirmed that opioid receptor agonists have good safety and tolerability as drugs for treating Alzheimer's disease.

[0102] It should be noted that the above embodiments are only examples, and the technical solutions of the various embodiments can be combined, and the order of the steps can be changed, all within the protection scope of the present invention.

[0103] The above is a detailed description of the use of the opioid receptor agonist provided by the present invention in the preparation of a drug for treating Alzheimer's disease. For a person skilled in the art, any obvious changes made to the present invention without departing from the essence of the present invention will constitute an infringement of the patent right of the present invention and the person shall bear the corresponding legal liability.

Claims

1. The use of opioid receptor agonists in the preparation of drugs for the treatment of Alzheimer's disease.

2. Use of opioid receptor agonists in the preparation of drugs for treating amyloid protein Aβ deposition or accumulation.

3. Use of opioid receptor agonists in the preparation of drugs for clearing / reducing amyloid protein Aβ.

4. Use of opioid receptor agonists in the preparation of drugs for improving / treating cognitive dysfunction.

5. The use according to claim 1, characterized in that: The Alzheimer's disease is associated with the deposition of amyloid Aβ.

6. The use according to any one of claims 1 to 5, characterized in that: The drug promotes the clearance of the amyloid protein Aβ by affecting the amyloid protein Aβ phagocytic ability of astrocytes; and / or, The drug reduces the accumulation of amyloid Aβ; and / or, The drug can improve cognitive dysfunction.

7. The use according to any one of claims 1 to 6, characterized in that: In the medicine, the effective dosage of the opioid receptor agonist is 0.5 to 50 mg / Kg.

8. The use according to any one of claims 1 to 7, characterized in that: The drug is in the form of an oral dosage form, an injection, or a suppository; Wherein, the oral dosage form is any one of a tablet, an oral solution, and a sustained-release dosage form.

9. The use according to any one of claims 1 to 8, characterized in that: An effective dose of 5 to 30 mg / Kg of the opioid receptor agonist is administered daily for 5 to 14 consecutive days; wherein the administration method is injection, and the effective dose is administered 1 to 3 times a day.

10. The use according to claim 8, characterized in that: The effective daily dosage of the tablet is 15 to 100 mg, and each administration is 5 to 30 mg; and / or, The effective daily dosage of the oral solution is 15 to 100 mg, with 5 to 30 mg for each administration; and / or, The effective daily dosage of the sustained-release dosage form is 20 to 50 mg, with 10 to 20 mg administered each time; and / or, The suppository is a suppository for rectal administration, and the effective dosage for daily administration is 10 to 100 mg, and 5 to 30 mg is administered each time.

11. The use according to any one of claims 1 to 10, characterized in that The opioid receptor agonist is selected from at least one of a μ opioid receptor agonist, a κ opioid receptor agonist, and a δ opioid receptor agonist.

12. The use according to claim 11, characterized in that: The μ opioid receptor agonist is at least one of morphine, morphine derivatives, fentanyl, sufentanil, remifentanil, methadone, piperazine and oxycodone.

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