Application of alpha-ketoglutaric acid in preparation of medicine and food for preventing or relieving postoperative pain

Abstract

The invention provides an application of alpha-ketoglutaric acid in preparation of a medicine and food for preventing or relieving postoperative pain. On the basis that a plurality of risk factors such as chronic neuropathic pain and postoperative chronic pain influenced by intestinal bacteria are closely related to intestinal bacteria change, and the intestinal bacteria are easily influenced in the perioperative period, the peripheral blood metabolite capable of preventing and treating the postoperative pain is explored from'intestinal bacteria-peripheral blood metabolite-spinal axis', and the results show that (1) the postoperative chronic pain can be prevented by eliminating the intestinal bacteria, and the postoperative chronic pain can be prevented by eliminating the intestinal bacteria; peripheral blood alpha-ketoglutaric acid is increased; (2) alpha-ketoglutaric acid in peripheral blood can be reduced in thoracotomy; (3) the alpha-ketoglutaric acid is supplemented by oral administration, so that the postoperative chronic pain can be prevented, and the excitability of spinal dorsal horn neurons can be reduced; and (4) the pain relieving effect of morphine can be synergistically enhanced by oral administration of alpha-ketoglutaric acid. The alpha-ketoglutaric acid can be used for postoperative analgesia and prevention of postoperative chronic pain.

Description

Technical Field

[0001] The present invention relates to the fields of biomedicine and food, and particularly to the use of α-ketoglutaric acid in the preparation of drugs and foods for preventing or alleviating postoperative pain. Background Art

[0002] Postoperative pain is an inflammatory pain caused by the stimulation of nociceptors due to postoperative chemical, mechanical or temperature changes, and belongs to nociceptive pain. It can be divided into postoperative acute pain and postoperative chronic pain. Among them, postoperative acute pain mainly occurs within 24 - 72 hours after surgery and usually lasts for 4 - 6 days. Postoperative chronic pain refers to pain related to surgery, with a pain duration exceeding the normal healing period (usually considered to exceed 3 months), excluding other pain causes (such as malignant tumors, infections, and pre-existing pain). Postoperative pain often triggers a series of stress responses, increasing cardiovascular system complications, respiratory system complications, and thromboembolism, etc., affecting the patient's immune function, digestive system function, and endocrine and metabolic functions, and seriously affecting the patient's postoperative quality of life. Therefore, postoperative analgesia is one of the important measures in the current fast-track surgery, an important means of preventing postoperative complications, and an effective means of comfortable medical care.

[0003] Currently, postoperative analgesia methods can be divided into non-drug therapies (such as physical therapy, music, distraction, etc.) and drug therapies. Commonly used drugs include opioid drugs (such as morphine, fentanyl, etc.), non-opioid drugs (such as acetaminophen, non-steroidal anti-inflammatory drugs, etc.), and local anesthetics (such as lidocaine, ropivacaine, etc.). Non-drug therapies include physical therapy (such as cold compress, hot compress, etc.), psychological therapy, acupuncture, etc. Although the implementation of multimodal analgesia and individualized treatment has improved the analgesic effect currently, the incidence of postoperative pain is still very high. It is reported that more than 80% of patients experience pain within 7 days after surgery, and 39% of patients experience "severe" to "extreme" postoperative pain. The incidence of postoperative chronic pain can reach 50 - 85% after amputation surgery, 5 - 65% after thoracotomy, 30 - 55% after cardiac surgery, and 20 - 50% after breast surgery.

[0004] In addition, although usually opioid drugs can obtain good analgesia by activating their specific receptors. However, in actual clinical work, due to the side effects of opioid analgesics (such as respiratory depression, nausea, vomiting, dizziness, tolerance), there are limitations in the use of drug doses and the use time.

[0005] Therefore, it is of particular significance to further develop new analgesic drugs or methods, especially non-opioid substances. Summary of the Invention

[0006] The present invention provides the use of α-ketoglutaric acid in the preparation of drugs and foods for preventing or alleviating postoperative pain, aiming to solve the above problems existing in the background art.

[0007] To achieve the above object, an embodiment of the present invention provides the use of α-ketoglutaric acid in the preparation of drugs and foods for preventing or alleviating postoperative pain.

[0008] Preferably, the α-ketoglutaric acid serves as the main active ingredient.

[0009] Preferably, the drug can be formulated into solid preparations, injections, sprays, liquid preparations, inhalation preparations or compound preparations.

[0010] Preferably, the drug further contains pharmaceutically acceptable excipients.

[0011] Preferably, the pain includes acute pain and chronic pain.

[0012] An embodiment of the present invention also provides the use of a composition containing α-ketoglutaric acid in the preparation of drugs and foods for preventing or alleviating postoperative pain.

[0013] Preferably, the α-ketoglutaric acid is used in combination with morphine.

[0014] Preferably, the composition can be formulated into solid preparations, injections, sprays, liquid preparations, inhalation preparations or compound preparations.

[0015] Preferably, the composition further contains pharmaceutically acceptable excipients.

[0016] Preferably, the pain includes acute pain and chronic pain.

[0017] Based on the fact that gut microbiota affects the chronicization of neuropathic pain, and many risk factors such as postoperative chronic pain are closely related to the alteration of gut microbiota, and gut microbiota is easily affected during the perioperative period, starting from the "gut microbiota - peripheral blood metabolite - spinal cord axis", the present invention explores peripheral blood metabolites that can prevent and treat postoperative pain, and finds that: (1) eliminating gut microbiota can prevent postoperative chronic pain and increase peripheral blood α-ketoglutaric acid; (2) thoracotomy can reduce peripheral blood α-ketoglutaric acid; (3) oral supplementation of α-ketoglutaric acid can prevent postoperative chronic pain and reduce the excitability of spinal dorsal horn neurons; (4) oral administration of α-ketoglutaric acid can synergistically enhance the analgesic effect of morphine. All of the above indicate that α-ketoglutaric acid can be used for postoperative analgesia and prevention of postoperative chronic pain.

[0018] The above solution of the present invention has the following beneficial effects:

[0019] (1) Through preclinical experiments, the present invention for the first time discovers that oral supplementation of α-ketoglutaric acid can prevent postoperative chronic pain and reduce the excitability of spinal dorsal horn neurons, providing a non-opioid substance for the prevention of postoperative chronic pain.

[0020] (2) Through preclinical experiments, the present invention for the first time discovers that oral α-ketoglutaric acid can synergistically enhance the analgesic effect of morphine. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 For gut microbiota depletion preventing chronic pain after thoracotomy; wherein A. Open field behavior; B. Mechanical pain threshold; C. Sucrose preference test to detect its depressive-like behavior; D. Novel object recognition to detect its cognition; E. Alpha diversity of gut microbiota; F. Beta diversity of gut microbiota; G. Heatmap of gut microbiota at family level; H. Abundance of gut microbiota at genus level; Control and C are both control groups without any treatment; Thoracotomy and T are both thoracotomy groups; Thoracotomy+ABX and T+ABX are both thoracotomy+gut microbiota depletion groups; Ns indicates no statistical difference, *p<0.05, **p<0.01, ***p<0.001, ****p<0.0001.

[0023] Figure 2 For gut microbiota depletion increasing the level of peripheral blood α-ketoglutaric acid; wherein, A. Heatmap of differential metabolites in peripheral blood of gut microbiota-depleted and normal rats reared in natural environment; B. Heatmap of differential metabolites in peripheral blood of gut microbiota-depleted and normal mice reared in SPF environment; C. Venn diagram of differential metabolites in peripheral blood under two rearing conditions; D. Volcano plot of common differential metabolites in peripheral blood under two rearing conditions; E, F, G. Quantitative diagrams and network diagrams of pain-related target genes of common down-regulated differential metabolites in peripheral blood under two rearing conditions; H. Relative levels of α-KG in peripheral blood of gut microbiota-depleted and normal rats reared in natural environment (from metabolomics); I. Quantitative detection of α-KG in peripheral blood of gut microbiota-depleted and normal rats reared in natural environment (from quantitative mass spectrometry); Control is the control group without any treatment; ABX is the gut microbiota depletion group; *p<0.05.

[0024] Figure 3Oral supplementation of α-ketoglutaric acid can inhibit the formation of chronic pain after thoracotomy in rats and prevent spinal dorsal horn sensitization. Among them, A. Flow chart of intervention from the operation day to 21 days after operation; B. Quantitative detection of peripheral blood α-KG; C. Open field behavior; D. Mechanical pain threshold; E. Novel object recognition result; F. Response amplitude of spinal dorsal horn electrical stimulation; G. Response frequency of spinal dorsal horn electrical stimulation; H. Flow chart of intervention from 7 days after operation to 21 days after operation; I. Mechanical pain threshold; Normal control is the normal control group without any treatment; Thoracotomy is the thoracotomy group; Thoracotomy+αKG is the thoracotomy + α-ketoglutaric acid supplementation group; Ns indicates no statistical difference, *p<0.05, **p<0.01, ***p<0.001, ****p<0.0001.

[0025] Figure 4 Oral supplementation of α-ketoglutaric acid can synergistically enhance the analgesic effect of morphine. Among them, Thoracotomy is the thoracotomy group; Thoracotomy+αKG is the thoracotomy + α-ketoglutaric acid supplementation group; Thoracotomy+MP is the thoracotomy + morphine group; Thoracotomy+MP+αKG is the thoracotomy + morphine + α-ketoglutaric acid supplementation group; *p<0.05, ****p<0.0001. Detailed implementation manners

[0026] To make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments.

[0027] Unless otherwise defined, all professional terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present invention.

[0028] Unless otherwise specifically stated, various raw materials, reagents, instruments and equipment used in the present invention can be obtained through the market or can be prepared by existing methods.

[0029] The present invention provides an application of α-ketoglutaric acid in the preparation of drugs and foods for preventing or alleviating postoperative pain in view of existing problems.

[0030] Preferably, the α-ketoglutaric acid is used as the main active ingredient.

[0031] Preferably, the drug can be made into solid preparations, injections, sprays, liquid preparations, inhalation preparations or compound preparations.

[0032] Preferably, the drug also contains pharmaceutically acceptable excipients.

[0033] Preferably, the pain includes acute pain and chronic pain.

[0034] An embodiment of the present invention also provides the use of a composition containing α-ketoglutaric acid in the preparation of a medicament and a food for preventing or alleviating postoperative pain.

[0035] Preferably, the α-ketoglutaric acid is used in combination with morphine.

[0036] Preferably, the composition can be made into a solid preparation, an injection, a spray, a liquid preparation, an inhalation preparation or a compound preparation.

[0037] Preferably, the composition further contains a pharmaceutically acceptable excipient.

[0038] Preferably, the pain includes acute pain and chronic pain.

[0039] Based on the fact that gut microbiota affects the chronicization of neuropathic pain, and many risk factors such as postoperative chronic pain are closely related to the changes in gut microbiota, and gut microbiota is easily affected during the perioperative period, starting from the "gut microbiota - peripheral blood metabolite - spinal cord axis", this invention explores peripheral blood metabolites that can prevent and treat postoperative pain, and finds that: (1) eliminating gut microbiota can prevent postoperative chronic pain and increase peripheral blood α-ketoglutaric acid; (2) thoracotomy can reduce peripheral blood α-ketoglutaric acid; (3) oral supplementation of α-ketoglutaric acid can prevent postoperative chronic pain and reduce the excitability of spinal dorsal horn neurons; (4) oral administration of α-ketoglutaric acid can synergistically enhance the analgesic effect of morphine. All of the above indicate that α-ketoglutaric acid can be used for postoperative analgesia and prevention of postoperative chronic pain.

[0040] The following is an elaboration through specific examples.

[0041] In this article, "α-KG" refers to α-ketoglutaric acid.

[0042] Example 1

[0043] To study the effect of gut microbiota on the formation of postoperative chronic pain, we used a combination of antibiotics (0.25 g / L vancomycin, 0.5 g / L metronidazole, 0.5 g / L neomycin sulfate and 0.5 g / L ampicillin) dissolved in deionized water to prepare an ABX mixture, which was provided for rats to drink freely from 24 h before surgery until the end of the behavioral test to achieve the purpose of gut microbiota deletion.

[0044] The gut microbiota was detected by 16S sequencing of intestinal contents, and it was found that: this method is effective and has a significant impact on the α diversity ( Figure 1 E), β diversity ( Figure 1 F), the abundance at the family level of gut microbiota ( Figure 1 G), and the abundance at the genus level of gut microbiota ( Figure 1 H).

[0045] Example 2

[0046] In order to construct a postoperative chronic pain model, we constructed a rat model of thoracotomy based on the characteristics of high incidence of chronic pain after thoracotomy. The specific steps are as follows:

[0047] Rats were intubated via the mouth after rapid induction with sevoflurane (4.5% sevoflurane with 100% oxygen) and connected to a small animal ventilator for mechanical ventilation, set to volume control mode, with tidal volume adjusted to 2 mL and respiratory rate set to 80 times / min. During the operation, a mixture of 2%-2.5% sevoflurane and 100% oxygen was used to maintain anesthesia, and the vital signs of the rats were closely monitored throughout the operation. After anesthesia, the rats were placed on a warming blanket, placed in the left lateral position, and the 4th-5th intercostal space on the right was located. A skin incision of about 3 cm long was made, and the subcutaneous tissue and muscle were separated layer by layer to fully expose the 4th-5th intercostal muscles. After the thorax was lifted, the intercostal muscles and pleura were cut, and the incision length was about 1.5 cm. The thorax was kept lifted during the incision to avoid damaging the lung lobe. Next, a rib retractor with blunt teeth was placed in the incision to retract the 4th and 5th ribs, maintaining a retraction width of about 1 cm. After 60 minutes, the retractor was removed (the incision was covered with saline gauze during this period), and a chest drain connected to a 5 mL syringe was left in the chest cavity. Subsequently, the intercostal muscles and pleural incisions were closed and ligated with 2-0 silk sutures, and the sutures spanned the 4th and 5th ribs to ensure a firm chest closure. After closing the pleural incision, we used a syringe to aspirate the gas in the chest cavity to restore the negative pressure in the chest cavity. Next, we used 2-0 silk and 4-0 nylon sutures to suture the muscles and skin in layers, respectively. Before the incision was finally closed, the assistant assisted in removing the chest drain and completed the incision closure operation at the same time to minimize the risk of air entering the chest cavity and causing pneumothorax. After the operation, we closely observed the respiratory rate and amplitude of the rats. After the rats resumed normal spontaneous breathing, the endotracheal tube was removed in time.

[0048] Example 3

[0049] In order to detect pain after thoracotomy, we used the Von Frey filament test to detect the mechanical pain behavior of rats. The specific steps are as follows:

[0050] The experimental animals were placed in the behavioral testing room 2 hours in advance to fully adapt to the new environment and reduce the impact of stress response on the experimental results. During the experiment, the animals were placed in a special metal cage to restrict their free movement and ensure that the test was carried out in a quiet state. Subsequently, von Frey filaments of different diameters and hardness were used to stimulate the animal 0.5mm next to the wound one by one, while ensuring that there was enough time interval between each stimulation so that the animal could return to the basic physiological state. Each animal was tested repeatedly multiple times, and the results of each test were recorded in detail.

[0051] The results showed that: (1) gut microbiota deletion significantly alleviated postoperative chronic pain ( Figure 1 B); (2) α-ketoglutaric acid supplementation significantly alleviated postoperative chronic pain ( Figure 3 D and Figure 3 I).

[0052] Example 4

[0053] To detect the motor ability of rats, we used an open field test, and the specific steps were as follows:

[0054] A wooden cube box was used for the test. The bottom plate of the box was divided into 25 squares with black lines. The squares along the box walls of the cube were called peripheral squares, and the rest were central squares. During the experiment, the mice were placed in the central square, and then their activities within 5 minutes were observed. The observation indexes were: the residence time in the central square, the residence time in the peripheral squares, the number of times crossing the central square, and the total number of crossed squares. The percentage of residence time in the central square and the number of times crossing the central square were negatively correlated with the anxiety level of the mice, that is, the shorter the percentage of residence time in the central square and the fewer the number of times crossing the central square, the higher the anxiety level of the mice. The total number of crossed squares reflected its activity ability. We found that thoracotomy had no effect on the motor ability of rats ( Figure 1 A).

[0055] To evaluate whether rats had depressive-like behaviors, we used a sucrose preference test for detection, and the specific steps were as follows: At 9 pm on the day before the test, all experimental animals were starved. During this process, we removed all food and water sources from the animal breeding cages until 9 am the next day. During this period, we prepared the experimental test box, which was equipped with two drinking tubes, containing fresh 1% sucrose solution and ordinary water respectively, and an appropriate amount of food was placed in the feeding trough. At 9 am the next day, we took out the starved experimental animals from the breeding cages and carefully placed them into the prepared experimental test box. Subsequently, within 12 hours, we continuously monitored and recorded the intakes of the two different solutions by the animals. By strictly calculating the intakes of the two different solutions by the animals, the sucrose preference ratio was calculated as: Sucrose preference ratio = sucrose intake / (sucrose solution intake + ordinary water intake) ( Figure 1 C).

[0056] Example 5

[0057] To detect the learning and memory ability of rats, we used novel object recognition for detection, and the specific steps were as follows:

[0058] During the learning phase, two identical items (A) were placed at symmetrical positions in the open field. The mice were placed in the open field for 10 minutes of adaptive learning, and the time spent by the mice exploring each item was recorded by video. After 24 hours, the mice were subjected to an item recognition test: one of the items A in the open field was replaced with a new item B, and the mice were placed in the open field for free exploration. The video was recorded for 10 minutes and the time spent by the mice exploring each item (TA and TB) was recorded, and the DI value of each mouse was calculated [DI = TB / (TA + TB)]. The item recognition memory of each group of animals was evaluated based on the DI value. A DI value above 0.5, and the higher the value, indicated better memory of the old item by the animals.

[0059] The results showed that: (1) Deleting intestinal bacteria had no significant effect on its learning and memory ( Figure 1 D); (2) Supplementing α-ketoglutaric acid could improve the learning and memory ability after surgery ( Figure 3 E).

[0060] Example 6

[0061] To detect changes in intestinal bacteria, we used intestinal bacteria 16sRNA sequencing for detection. The specific steps are as follows:

[0062] First, the rats were anesthetized with sevoflurane, and then their cecum was quickly dissected and the contents were collected. To ensure the quality of the samples, the collected contents were immediately frozen in liquid nitrogen for later use. Next, we used a soil DNA kit to efficiently extract the total microbial DNA. After extraction, the ND-2000 spectrophotometer was used to accurately measure the DNA concentration, and the quality of the extracted genomic DNA was detected by 1% agarose gel electrophoresis. The extracted high-quality DNA could be directly used for subsequent experiments or stored in aliquots at -80°C for long-term preservation. In the PCR amplification stage, we selected ABI ND-2000 spectrophotometer to accurately measure the DNA concentration, and the quality of the extracted genomic DNA was detected by 1% agarose gel electrophoresis. The extracted high-quality DNA could be directly used for subsequent experiments or stored in aliquots at -80°C for long-term preservation. In the PCR amplification stage, we selected ABI 9700 PCR thermal cycler was used to specifically amplify the hypervariable regions V3-V4 of the bacterial 16S rDNA gene. The primer sequences used for amplification were: forward primer ACTCCTACGGGAGGCAGCA and reverse primer GGACTACHVGGGTWTCTAAT. The amplification products were used as templates to construct an Illumina Miseq sequencing library. All sequencing work was accurately completed on the Illumina Miseq platform of Shanghai Majorbio Bio-pharm Technology Co., Ltd. After strict filtering and trimming of the sequencing data, it was accurately classified into different operational taxonomic units (OTUs), with the difference degree controlled within 0.03, equivalent to maintaining 97% sequence similarity. Subsequently, a series of representative sequences were generated and classified in detail based on the SILVA database (Release115). This process not only achieved a comprehensive analysis of microbial diversity and abundance in different samples, but also provided strong data support for revealing community structure and phylogenetic processes.

[0063] The results showed that antibiotic treatment had significant effects on the α-diversity ( Figure 1 E), β-diversity ( Figure 1 F), family-level abundance of intestinal bacteria ( Figure 1 G), and genus-level abundance of intestinal bacteria ( Figure 1 H).

[0064] Example 7

[0065] To screen out peripheral blood metabolites closely related to intestinal bacteria, we collected blood samples from the right ventricle of rats and then centrifuged them at a speed of 3000 revolutions per minute for 10 minutes to extract plasma for metabolomics detection. The specific steps were as follows:

[0066] Take 100 μL of the sample and put it into an EP tube, add 300 μL of methanol and 10 μL of internal standard, vortex for 30 s, ultrasonically treat for 10 min (placed in ice water), and then incubate at -20 °C for 1 h to precipitate proteins. Then, centrifuge at a speed of 13,000 revolutions per minute at 4 °C for 15 minutes. The supernatant (200 μL) was transferred to a liquid chromatography-mass spectrometry (LC-MS) vial. Quality control samples were prepared by mixing equal amounts of the supernatants of all samples. LC-MS analysis was performed using an ultra-high performance liquid chromatography (UHPLC) system and a UPLCSS T3 chromatographic column coupled with Q Exactive. We found the differences in peripheral blood metabolites between normal rats raised in a natural environment and rats treated with multiple antibiotics. A total of 1450 metabolites were detected in the two groups, among which 150 were differential metabolites (such as αKG, butyric acid) ( Figure 2A). These metabolites were compared with the differential metabolites in the peripheral blood of normal rats and rats treated with multiple antibiotics reared in a SPF environment reported by John R Speakman in Cell Reports ( Figure 2 B), and it was found that the breeding environment had a very obvious impact on the peripheral blood metabolites. They detected only 153 metabolites, and only 6 of them were differential metabolites shared by the two conditions ( Figure 2 C and 2D).

[0067] Example 8

[0068] To screen for peripheral blood metabolites directly related to pain, we conducted a detailed comparative analysis of the previously screened differential metabolites with the known drug targets of pain-related diseases in public databases. These public databases cover authoritative resources such as DrugBank, Therapeutic Target Database (TTD), and PubChem. After completing the preliminary comparison, we further used network pharmacology methods to construct a multi-level interaction network diagram containing the screened metabolites, their potential action targets, and the known drug targets of pain-related diseases. The construction of this network diagram not only reveals the complex relationship between metabolites and the drug targets of pain-related diseases, but also the determination of each pair of metabolite-drug target relationships is based on solid support from scientific literature and experimental data, thus ensuring the rigor and credibility of the overall analysis. According to this method, we obtained the quantitative diagrams and network diagrams of the target genes related to the down-regulated peripheral blood differential metabolites common to the two breeding conditions ( Figure 2 E, 2F, 2G), and screened out the metabolite α-ketoglutaric acid.

[0069] Example 9

[0070] To accurately quantify the effects of gut microbiota deletion and surgery on the level of α-ketoglutaric acid in peripheral blood, as well as the effectiveness of supplementing α-ketoglutaric acid from drinking water, we detected the level of peripheral α-ketoglutaric acid by quantitative mass spectrometry. The specific steps are as follows:

[0071] Take 50 μL of serum sample in a 1.5 mL centrifuge tube, add 50 μL of acetonitrile (containing 0.1 μg of internal standard), vortex, centrifuge at 15000 g for 10 minutes, take the supernatant into an injection vial, and detect it by Shimadzu UPLC-ESI-MS / MS. Chromatographic conditions: Analytical column: Waters Acquity UPLC BEH C18 column (2.1×100 mm, 1.7 μm), mobile phase: 10% methanol, 90% 0.05% triethylamine aqueous solution (containing 0.1% acetic acid), flow rate: 0.25 mL / min, column temperature: 30 °C.

[0072] Results showed that: (1) gut microbiota deletion significantly increased the level of α-ketoglutaric acid in peripheral blood ( Figure 2 H and 2I); (2) surgery significantly decreased the level of α-ketoglutaric acid in peripheral blood, while supplementation of α-ketoglutaric acid in drinking water could increase its level ( Figure 3 B).

[0073] Example 10

[0074] To increase the level of α-ketoglutaric acid in peripheral blood of animals, we dissolved α-ketoglutaric acid in deionized water to prepare a 2% α-ketoglutaric acid solution, which was freely available for rats to drink from 24 h before surgery until the end of behavioral tests.

[0075] Results showed that this method significantly increased the level of α-ketoglutaric acid in peripheral blood of animals ( Figure 3 B).

[0076] Example 11

[0077] To detect the mechanism by which α-ketoglutaric acid intervention affects the formation of postoperative chronic pain, we used electrophysiological methods to detect the excitability of spinal dorsal horn neurons. The specific steps were as follows:

[0078] Adult rats were anesthetized with urethane, and the spinal cord corresponding to the 4th - 5th intercostal nerves (the site of the surgical incision) was quickly removed and placed in an ice - water mixture. The pia mater was stripped off, and the spinal cord was sliced into 300 - μm sections using a vibratome. The spinal cord slices were transferred to a perfusion bath and stabilized for 1 - 2 hours, and the spontaneous action potential activity of spinal dorsal horn neurons was recorded using the whole - cell patch - clamp technique.

[0079] Results showed that α-ketoglutaric acid intervention significantly decreased the firing frequency and amplitude of spinal dorsal horn neurons ( Figure 3 F and Figure 3 G).

[0080] Example 12

[0081] To test whether morphine and α-ketoglutaric acid have a synergistic effect in the early stage of postoperative pain, we dissolved 0.5 mg / kg morphine in deionized water and intraperitoneally injected it into rats 0.5 h before Von Frey filament testing.

[0082] Results showed that morphine and α-ketoglutaric acid had a synergistic effect ( Figure 4 ).

[0083] Statistical analysis: Data were expressed as mean ± SEM. Two - way ANOVA or mixed - factor ANOVA (repeated - measures ANOVA) was used for statistical analysis. All statistical analyses were performed using GraphPad Prism 10. P < 0.05 was considered statistically significant.

[0084] The above are the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. Application of α-ketoglutaric acid in the preparation of medicines and foods for preventing or alleviating postoperative pain.

2. The use according to claim 1, characterized in that: The α-ketoglutaric acid serves as a main active ingredient.

3. The use according to claim 1 or 2, characterized in that: The medicine can be prepared into solid preparations, injections, sprays, liquid preparations, inhalation preparations or compound preparations.

4. The use according to claim 1 or 2, characterized in that: The medicine also contains pharmaceutically acceptable excipients.

5. The use according to claim 1 or 2, characterized in that: The pain includes acute pain and chronic pain.

6. Use of a composition containing α-ketoglutaric acid in the preparation of medicines and foods for preventing or alleviating postoperative pain.

7. The use according to claim 6, characterized in that: The α-ketoglutarate is used in combination with morphine.

8. The use according to claim 6 or 7, characterized in that: The composition can be prepared into a solid preparation, an injection, a spray, a liquid preparation, an inhalation preparation or a compound preparation.

9. The use according to claim 6 or 7, characterized in that: The composition further contains a pharmaceutically acceptable excipient.

10. The use according to claim 6 or 7, characterized in that: The pain includes acute pain and chronic pain.

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