Application of naltrexone in the preparation of drugs for treating hyperuricemia

Abstract

This invention relates to naltrexone, specifically to its application in the preparation of drugs for treating hyperuricemia. This invention is the first to discover that naltrexone can inhibit xanthine oxidase activity, thereby inhibiting uric acid production and effectively reducing uric acid levels in the serum of hyperuricemic mice, thus treating hyperuricemia. Naltrexone can also improve damage caused by renal tubular dilation and alleviate the progression of fibrosis, thereby reducing kidney damage. Furthermore, naltrexone treatment did not cause liver damage and the dosage used was lower than that of positive control drugs, indicating higher safety. The naltrexone described in this invention can be used as an active ingredient in drugs for lowering uric acid and / or treating hyperuricemia, broadening the application of naltrexone and providing a new option for drugs for lowering uric acid and / or treating hyperuricemia.

Description

Technical Field

[0001] This invention relates to naltrexone, and more particularly to the use of naltrexone in the preparation of drugs for treating hyperuricemia. Background Technology

[0002] Uric acid is produced by the liver through the metabolism of purine compounds from dietary intake (approximately 20%) and the breakdown of purine compounds in the body (approximately 80%). About two-thirds of uric acid is excreted through the kidneys, and one-third through the digestive tract. Uric acid is filtered by the glomeruli, reabsorbed by the proximal tubules, secreted, and then reabsorbed again after secretion. The unabsorbed portion is excreted in the urine. Under normal circumstances, the body contains approximately 1200 mg of uric acid, with about 600 mg newly generated and 600 mg excreted daily, maintaining a balance. Elevated blood uric acid levels can cause gout and are also associated with the development of diseases of the kidneys, endocrine system, metabolism, and cardiovascular system. The main clinical symptom of hyperuricemia is elevated blood uric acid. Approximately 5%–12% of patients with hyperuricemia eventually develop gout, experiencing recurrent gouty arthritis, interstitial nephritis, and tophi formation. In severe cases, joint deformities or uric acid urinary tract stones may occur. The kidneys are an important site for clearing uric acid. When the level of uric acid in the blood is very high, excess urate crystals will be deposited in the renal tubules and renal interstitium. The obstructed uric acid can activate local chronic inflammation, immune damage, and microvascular lesions in the kidneys, leading to the development of chronic kidney disease.

[0003] Currently, commonly used uric acid-lowering drugs in my country mainly fall into two categories: those that inhibit uric acid synthesis and those that promote uric acid excretion. Drugs that inhibit uric acid synthesis reduce uric acid production by inhibiting xanthine oxidase activity. Commonly used drugs include allopurinol and febuxostat. Allopurinol can cause skin allergic reactions and liver and kidney damage; in severe cases, it can lead to fatal exfoliative dermatitis, severe erythema multiforme drug eruption, toxic epidermal necrolysis, and other hypersensitivity syndromes. Adverse reactions of febuxostat include liver damage, nausea, and rash. Benzbromarone, a representative drug that promotes uric acid excretion, inhibits renal tubular uric acid reabsorption by inhibiting renal tubular urate transporter 1 (URAT1) and glucose transporter 9 (GLUT9), thereby increasing uric acid excretion and lowering serum uric acid levels. However, it requires urine alkalization to adjust the urine pH to 6.2-6.9 during administration. Adverse reactions include gastrointestinal discomfort, diarrhea, rash, and liver damage. These clinically used drugs have strong side effects or adverse reactions, placing a significant burden on the body. Therefore, it is urgent to find safer and more effective uric acid-lowering drugs. Summary of the Invention

[0004] Purpose of the invention

[0005] In view of the above-mentioned technical deficiencies, the primary objective of this invention is to provide the application of naltrexone in the preparation of drugs for lowering uric acid and / or treating hyperuricemia. The naltrexone can effectively reduce the serum uric acid level in animals, can play a role in treating hyperuricemia, and has no obvious side effects.

[0006] Technical Solution

[0007] The objective of this invention is achieved through the following technical solution:

[0008] Application of naltrexone in the preparation of drugs for the treatment of hyperuricemia.

[0009] Application of naltrexone in the preparation of drugs for treating kidney injury or renal fibrosis.

[0010] Furthermore, the use of pharmaceutical formulations with naltrexone as the active ingredient in the preparation of drugs for lowering uric acid and / or treating hyperuricemia.

[0011] In the preparation of drugs for lowering uric acid and / or treating hyperuricemia, naltrexone is used as the active ingredient in the development of pharmaceutical formulations, including oral solid and liquid formulations, patches, ointments, creams, gels, or sprays.

[0012] Specifically as follows:

[0013] To find compounds that can effectively reduce serum uric acid levels in animals, we first targeted xanthine oxidase and URAT1, and then used high-throughput virtual screening to further evaluate the therapeutic effects of small molecule compounds on hyperuricemia in vivo and in vitro.

[0014] This invention first utilizes the structures of xanthine oxidase and URAT1 targets from the PDB database, and then employs the Chemdiv and Zinc databases to screen for binding sites. Preliminary docking and further validation of compounds with targets were performed using PyMOL 2.6.0 and MOE software, respectively, revealing that naltrexone binds to xanthine oxidase with the highest score. A mouse model of hyperuricemia was established by intraperitoneal injection of potassium oxonate and gavage administration of hypoxanthine. Histopathological changes and the degree of fibrosis in the mice were observed using HE staining, PAS staining, and Masson staining to investigate the effects of naltrexone on lowering uric acid and treating hyperuricemia.

[0015] Beneficial effects

[0016] Naltrexone is an orally active competitive opioid receptor antagonist. Structurally and functionally similar to the opioid antagonist naloxone, naltrexone has higher oral bioavailability and a longer biological half-life. The U.S. Food and Drug Administration approved naltrexone hydrochloride for the treatment of opioid addiction in 1984. Studies have found that low-dose naltrexone has pharmacological effects not present at normal doses: low-dose naltrexone exerts anti-inflammatory effects by inhibiting non-opioid receptors. For example, low-dose naltrexone has been shown to antagonize TOIL-like receptor complexes in the body, reducing the production of pro-inflammatory cytokines, active and excitatory amino acids, and reducing the generation of neurotoxic peroxides such as NO and TNF-α. Low-dose naltrexone can also downregulate the activity of macrophages, T cells, and B cells, and block inflammatory markers such as tumor necrosis factor and interleukin-6, exerting biological effects of inhibiting inflammatory responses and anti-tumor activity. However, there are no literature reports on naltrexone treatment for hyperacidity.

[0017] This invention is the first to discover that naltrexone can inhibit xanthine oxidase activity, thereby inhibiting uric acid production and effectively reducing uric acid in the serum of hyperuricemic mice, thus playing a role in treating hyperuricemia; naltrexone can also improve damage caused by renal tubular dilation and alleviate the progression of fibrosis, thereby reducing kidney damage; in addition, naltrexone treatment did not cause liver damage and the dosage used was less than that of positive control drugs, indicating higher safety.

[0018] The naltrexone described in this invention can be used as an active ingredient in drugs for lowering uric acid and / or treating hyperuricemia, thus broadening the application of naltrexone and providing a new option for drugs for lowering uric acid and / or treating hyperuricemia. Attached Figure Description

[0019] Figure 1 Molecular docking diagram of naltrexone and xanthine oxidase;

[0020] Figure 2 Statistical graph showing the effect of naltrexone on serum uric acid levels in a mouse model of hyperuricemia;

[0021] Figure 3 Statistical chart showing the effect of naltrexone on serum xanthine oxidase activity in hyperuricemia model mice;

[0022] Figure 4 Schematic diagram of the effect of naltrexone on renal pathological damage in a mouse model of hyperuricemia;

[0023] Figure 5 Schematic diagram of the effects of naltrexone on pathological damage to other organs in a mouse model of hyperuricemia. Detailed Implementation

[0024] Example 1 Molecular docking

[0025] The 2D structures of small molecule ligands were obtained from the PubChem database (http: / / pubchem.ncbi.nlm.nih.gov / ), and their 3D structures were created using Chem Office 20.0 software and saved as mol2 files. Then, the RCSBPDB database (http: / / www.rcsb.org / ) was used to screen for protein targets and high-resolution crystal structures as molecular docking acceptors. PyMOL 2.6.0 software was used to perform operations such as dehydration and dephosphaterization on the proteins, and the results were saved as PDB files. Molecular Operating Environment 2019 software was used to minimize the energy of the compounds, preprocess the target proteins, and identify active pockets. Finally, molecular docking was performed using MOE 2019 with 50 operations. The binding activity was evaluated based on the binding energy, and the results were visualized using PyMOL 2.6.0 and Discovery Studio 2019 software. Figure 1 .

[0026] According to the binding results, Thr262, Asp360, and Asn351 residues on the xanthine oxidase receptor form hydrogen bonds with naltrexone, while residues Glu263 and Ser359 form carbon-hydrogen interactions with naltrexone. Additionally, ALa338, Leu74, Val342, and Phe337 residues on the receptor form hydrophobic interactions with naltrexone. Naltrexone can enter the binding domain of the xanthine oxidase target protein, with a docking energy of -7.0655 kcal / mol. Generally, a docking energy < -4.25 kcal / mol indicates some binding activity, < -5.0 kcal / mol indicates good binding activity, and < -7.0 kcal / mol indicates strong binding activity. The docking results indicate that naltrexone has strong binding activity with xanthine oxidase.

[0027] Example 2: Animal in vivo uric acid-lowering activity experiment

[0028] 1. Laboratory animals

[0029] This invention selected male KM mice weighing approximately 18-20g and housed them under standard conditions: temperature 25±2℃, humidity 50%-70%, alternating 12-hour light and dark cycles, free access to food and water, and replacement of wood shavings bedding every two days. Experiments began after the mice had adapted to the environment for 7 days. The mice were randomly divided into four groups of five mice each: a control group (NC), a hyperuricemia model group (HUA), a naltrexone treatment group (Naltrexone, 5mg / kg), and a febuxosta treatment group (Febuxosta, 5mg / kg).

[0030] 2. Establishment and administration of a mouse model of hyperuricemia

[0031] Except for the control group, which received 0.5% sodium carboxymethyl cellulose, the remaining three groups were administered potassium oxonate and hypoxanthine to establish the model. One hour after model establishment, the mice were administered the drugs according to their respective groups for a total of 7 days. Two hours after administration on the seventh day, the mice were anesthetized and blood was collected from their orbits. They were then sacrificed, and their organs were dissected and fixed for subsequent pathological staining analysis. The organ tissues were stored at -80°C.

[0032] 3. Serum uric acid level detection

[0033] After centrifuging the blood sample at 3000 rpm for 10 minutes, the clear supernatant was aspirated for testing. The relevant biochemical indicators were detected using a uric acid reagent kit (No. C012-2-1) purchased from Nanjing Jiancheng Company.

[0034] 4. Experimental Results

[0035] The results are as follows Figure 2 As shown, compared with the control group (NC) mice (approximately 40 μM), the hyperuricemia model group (HUA) mice had a serum uric acid level of approximately 220 μM, indicating successful model establishment. The naltrexone group mice had a serum uric acid level of approximately 98 μM, significantly lower than the HUA group, while the positive control group (Febuxosta) mice had a serum uric acid level of approximately 110 μM, indicating that naltrexone has a good uric acid-lowering effect.

[0036] Example 3: Effect of naltrexone on xanthine oxidase activity in vivo

[0037] 1. Reagents used: Nanjing Jiancheng xanthine oxidase (XOD) test kit, product number A002-1-1.

[0038] 2. Operating steps:

[0039] After centrifuging the blood sample at 3000 rpm for 10 minutes, the clear supernatant was aspirated for testing. 50 μl of the serum sample to be tested was added, and reagents were added in the order specified in the instructions. After mixing, the sample was incubated in a water bath at 37°C for 20 minutes. The stop solution was then added, and the absorbance value was measured after mixing. The wavelength was selected as 530 nm.

[0040] 3. Experimental Results

[0041] The results are as follows Figure 3As shown, compared with the control group (NC) mice, the serum xanthine oxidase activity in the hyperuricemia model group (HUA) mice was approximately 5.6 U / L, indicating that xanthine oxidase activity was increased and uric acid production was increased in the hyperuricemia model. The serum xanthine oxidase activity in the naltrexone group was approximately 3.8 U / L, significantly lower than that in the HUA group. In contrast, the serum xanthine oxidase activity in the febuxosta positive control group was approximately 3.6 U / L, indicating that naltrexone can inhibit xanthine oxidase activity, reduce uric acid production, and thus lower uric acid levels.

[0042] Example 4: HE staining and Masson staining of pathological sections demonstrated that naltrexone alleviates kidney damage.

[0043] like Figure 4 As shown, HE staining results indicated that the hyperuricemia model (HUA group) could induce renal tubular dilation, basement membrane thickening, renal tubular epithelial cell necrosis, and renal tubular brush border detachment in mice. Naltrexone administration group could improve the damaging effects of renal tubular dilation, thereby playing a protective role for the kidneys. Masson staining results showed that naltrexone administration group significantly alleviated renal fibrosis and the effect was significantly better than that of positive control group.

[0044] In addition, see Figure 5 In the naltrexone group, the alveoli and lung tissue structure were intact, without damage, with a clear reticular structure and no inflammatory cell infiltration, indicating no lung damage. The liver tissue in the naltrexone group had a clear structure, including tightly and orderly arranged hepatocytes, and a clear distribution of blood vessels and bile ducts, without ill-defined, eosinophilic cell debris or inflammatory cell infiltration, indicating no liver damage. The brain structure in the naltrexone group was clear and intact, without inflammatory cell infiltration, with intact nerve cell structure, uniform staining of nerve fibers in the white matter, and neat, clear texture, indicating no brain damage. The spleen corpuscles were not enlarged, follicles were not increased, and the structure was intact and clear, indicating no spleen damage.

[0045] In conclusion, naltrexone treatment can reduce kidney damage and fibrosis without significant side effects.

Claims

1. Application of naltrexone as the sole active ingredient in the preparation of drugs for the treatment of hyperuricemia.

2. The application according to claim 1, characterized in that, The naltrexone is a pharmaceutical preparation in which naltrexone is the only active substance.

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