Stem cell exosome as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of biological medicines, and particularly relates to a stem cell exosome as well as a preparation method and application thereof. The stem cell exosome is cultured by using pilose antler stem cells, and on the basis of a traditional exosome culture medium extraction process, the pilose antler stem cell exosome can be induced to have the activity of reducing uric acid and have the potential of treating gout by adding phellinus igniarius polysaccharide for induction culture.

Description

Technical Field

[0001] This invention belongs to the field of biomedical technology, specifically relating to a stem cell exosome, its preparation method, and its application. Background Technology

[0002] Gout is a metabolic disease caused by a series of inflammatory reactions resulting from urate crystal deposition due to metabolic disorders of purines or reduced uric acid excretion by the kidneys. When serum uric acid levels rise to a supersaturated state, it is deposited in the joints, periarticular tissues, and organs via extracellular fluid, causing a group of gout syndromes, including tophi, uric acid kidney stones, gouty arthritis, and gouty nephropathy. Studies show that lowering serum uric acid levels can reduce the formation of urate crystals, thereby preventing gout attacks. Maintaining normal uric acid levels in the long term helps reduce the frequency and severity of gout recurrences. In conclusion, there is a direct relationship between lowering uric acid and managing gout; controlling uric acid levels is a key measure for the prevention and treatment of gout.

[0003] Currently, the main treatments for gout are to reduce the incidence of hyperuricemia by inhibiting excessive uric acid production and promoting uric acid excretion, as well as by inhibiting inflammatory cytokines. Commonly used Western medicines for gout treatment include diclofenac sodium, colchicine, benzbromarone tablets, allopurinol tablets, and propofol. These medications can effectively relieve pain during gout attacks; however, some have significant side effects, and high doses or long-term use can harm the body.

[0004] Exosomes are extracellular vesicles secreted by cells, ranging in diameter from 30 to 150 nm. They are widely distributed in various body fluids and are rich in bioactive substances such as proteins, nucleic acids (mRNA, miRNA, etc.), and lipids. These components endow exosomes with unique biological functions. Exosomes have low immunogenicity, avoiding rapid clearance by the immune system, and can serve as natural drug carriers. Simultaneously, they can transmit biological information between cells, regulate the physiological functions of recipient cells, and participate in various physiological and pathological processes. Therefore, research on exosome-based treatments for gout is anticipated in this field. Summary of the Invention

[0005] Therefore, the first objective of this invention is to provide a stem cell exosome that has the effect of lowering uric acid and can be used for the treatment of gout; A second objective of this invention is to provide a method for preparing the aforementioned stem cell exosomes; A third object of the present invention is to provide the use of the said stem cell exosomes in the preparation of a drug for treating gout.

[0006] To solve the above-mentioned technical problems, the present invention provides a method for preparing stem cell exosomes, comprising the following steps: (1) Deer antler tissue was taken and deer antler mesenchymal stem cells were obtained; (2) The isolated deer antler mesenchymal stem cells were added to a serum-free culture medium containing Phellinus linteus polysaccharide for amplification culture; (3) Collect the culture and extract the exosomes to obtain deer antler stem cell exosomes.

[0007] Specifically, in the method for preparing stem cell exosomes, step (1) of separating the deer antler mesenchymal stem cells includes adding the deer antler tissue to a digestive solution for digestion, and obtaining the deer antler mesenchymal stem cells by filtration and centrifugation.

[0008] Specifically, in the method for preparing stem cell exosomes, step (1) includes: The digestive fluid contains 1-1.5 wt% type I collagenase; and / or, The digestion step is performed at a temperature of 35-37°C for 0.5-1 hour.

[0009] Specifically, in the method for preparing stem cell exosomes, in step (2), the concentration of the Sanghuang polysaccharide in the serum-free culture medium is 2-3 μM.

[0010] Specifically, in the method for preparing stem cell exosomes, the Sanghuang polysaccharide is a polysaccharide extract derived from the fruiting body of Sanghuang.

[0011] Specifically, in the method for preparing stem cell exosomes, the serum-free culture medium may also contain conventional growth factors such as transforming growth factor, fibroblast growth factor, epidermal growth factor, insulin-like growth factor, vascular endothelial growth factor, hepatocyte growth factor, glutathione, interleukin-6, interleukin-10, or tumor necrosis factor receptor.

[0012] Specifically, in the method for preparing stem cell exosomes, the parameters of the amplification step in step (2) include: culture temperature of 35-37℃ and culture at 5% v / v CO2 for 36-60h.

[0013] Specifically, in the method for preparing stem cell exosomes, step (3) includes the following steps: taking the culture, performing solid-liquid separation and collecting the supernatant, and obtaining deer antler stem cell exosomes after impurity removal, filtration, centrifugation and washing.

[0014] Specifically, in the method for preparing stem cell exosomes, step (3) further includes adding dodder exosomes to the deer antler stem cell exosomes for mixing, so as to obtain the desired stem cell exosomes.

[0015] Specifically, in the method for preparing the stem cell exosomes, the mass ratio of the deer antler stem cell exosomes to the dodder seed exosomes is 1-3:1.

[0016] Specifically, the method for preparing stem cell exosomes includes the following extraction steps for Cuscuta exosomes: The dodder tissue was mixed with pre-cooled PBS phosphate buffer at low temperature and ground thoroughly to form a homogenate. After preliminary filtration, the initial filtrate was obtained. Centrifuge the initial filtrate at 300-2000×g for 10-30 minutes and collect the first supernatant; Continue to centrifuge the first supernatant at 10,000-20,000 × g for 30-60 minutes, and collect the second supernatant; Continue to centrifuge the second supernatant at 100,000-150,000×g for 60-120 minutes, discard the supernatant and collect the precipitate; The precipitate was then washed with PBS phosphate buffer to obtain the final product.

[0017] The present invention also discloses a stem cell exosome, which is prepared by the method described above.

[0018] The present invention also discloses the use of the stem cell exosomes in the preparation of drugs for treating gout or lowering uric acid.

[0019] The stem cell exosomes described in this invention are cultured using deer antler stem cells. Based on the traditional exosome culture medium extraction process, by adding Phellinus linteus polysaccharide for induction culture, the deer antler stem cell exosomes can be induced to have uric acid-lowering activity. Compared with deer antler stem cell exosomes cultured alone, they have significant uric acid-lowering performance.

[0020] The stem cell exosomes described in this invention are extracted from dodder seed. The activity of the exosomes has been verified to have a certain uric acid-lowering effect. Although the activity cannot reach the effect of the positive control, it still has good development potential.

[0021] The stem cell exosomes of the present invention are obtained by combining the deer antler stem cell exosomes and dodder seed exosomes to form an exosome composition. The uric acid-lowering activity of the two is further enhanced to achieve a synergistic effect, effectively enhancing the potential effect of treating gout. Detailed Implementation

[0022] The invention's objective, technical solution, and beneficial effects will be further explained in detail below.

[0023] In the following embodiments of the present invention, a stem cell exosome or stem cell exosome composition is provided that can effectively reduce uric acid levels and thus treat gout symptoms. The stem cell exosome or stem cell exosome composition comprises deer antler stem cell exosomes as the main active ingredient, and selectively mixed with dodder seed exosomes. In the following embodiments of the present invention, both the deer antler stem cell exosomes and the dodder seed exosomes exhibit appropriate uric acid-lowering properties and effects, and their synergistic application further enhances the effect.

[0024] In the following embodiments of the present invention, the deer antler stem cell exosomes are exosome components obtained by traditional deer antler stem cell exosome preparation methods using Phellinus linteus polysaccharide as an inducing culture. Phellinus linteus polysaccharide, as an active ingredient, can induce the production of deer antler stem cell exosomes and enhance their uric acid-lowering performance, enabling them to be used for the treatment of gout symptoms.

[0025] The present invention provides a method for preparing stem cell exosomes in the following embodiments, comprising the following steps: (1) Deer antler tissue was taken and deer antler mesenchymal stem cells were obtained; (2) The isolated deer antler mesenchymal stem cells were added to a serum-free culture medium containing Phellinus linteus polysaccharide for amplification culture; (3) Collect the culture and extract the exosomes to obtain deer antler stem cell exosomes.

[0026] As an exemplary embodiment, the separation step of the deer antler mesenchymal stem cells includes the step of adding the deer antler tissue to a digestive solution for digestion, and the step of obtaining the deer antler mesenchymal stem cells by filtration and centrifugation.

[0027] As an exemplary embodiment, the digestive fluid contains 1-1.5 wt% type I collagenase.

[0028] As an exemplary embodiment, the temperature of the digestion step is 35-37°C, and the digestion time is 0.5-1h.

[0029] As an exemplary embodiment, in step (2), the concentration of the Phellinus linteus polysaccharide in the serum-free culture medium is 2-3 μM.

[0030] As an exemplary embodiment, the Sanghuang polysaccharide is a polysaccharide extract extracted from the fruiting body of Sanghuang.

[0031] As an exemplary embodiment, the serum-free culture medium can be any commercially available serum-free culture medium product commonly used in the art.

[0032] As an exemplary embodiment, the serum-free culture medium may also contain conventional growth factors such as transforming growth factor, fibroblast growth factor, epidermal growth factor, insulin-like growth factor, vascular endothelial growth factor, hepatocyte growth factor, glutathione, interleukin-6, interleukin-10, or tumor necrosis factor receptor.

[0033] As an exemplary implementation, the parameters of the amplification step in step (2) include: culture temperature of 35-37℃ and culture at 5% v / v CO2 for 36-60h.

[0034] As an exemplary embodiment, in step (3), the exosome extraction step includes: taking the culture, performing solid-liquid separation and collecting the supernatant, and obtaining deer antler stem cell exosomes after impurity removal, filtration, centrifugation and washing.

[0035] Furthermore, the method of the present invention also found that exosomes extracted from dodder seed also have the effect of lowering uric acid, and can be mixed with the deer antler stem cell exosomes, that is, the deer antler stem cell exosomes and dodder seed exosomes are mixed to obtain the desired stem cell exosomes.

[0036] As an exemplary embodiment, the mass ratio of the deer antler stem cell exosomes to the dodder seed exosomes is 1-3:1, preferably 2:1.

[0037] As an exemplary embodiment, the present invention also provides a method for extracting the dodder exosomes, comprising the following steps: The dodder tissue was mixed with pre-cooled PBS phosphate buffer at low temperature and ground thoroughly to form a homogenate. After preliminary filtration, the initial filtrate was obtained. Centrifuge the initial filtrate at 300-2000×g for 10-30 minutes and collect the first supernatant; Continue to centrifuge the first supernatant at 10,000-20,000 × g for 30-60 minutes, and collect the second supernatant; Continue to centrifuge the second supernatant at 100,000-150,000×g for 60-120 minutes, discard the supernatant and collect the precipitate; The precipitate was then washed with PBS phosphate buffer to obtain the final product.

[0038] The deer antler stem cell exosomes and the dodder seed exosomes described in this invention both exhibited feasible uric acid-lowering effects and can be used as potential treatments for gout.

[0039] Example 1 In this embodiment, the preparation and extraction of the deer antler stem cell exosomes can be carried out using existing culture methods.

[0040] In this embodiment, fresh antler tissue from healthy sika deer was selected, and mesenchymal tissue was obtained under aseptic conditions. The antler tissue was cut into small pieces (approximately 2 mm in size) and placed in a digestive solution containing 1% type I collagenase. Digestion was carried out at 37°C for 0.5 hours, with gentle agitation intermittently to release cells. After digestion, a single-cell suspension was obtained by filtration through a cell filter. The digestive enzymes were removed by centrifugation, and the cells were resuspended in PBS. Cells were seeded in culture dishes and cultured in serum-free DMEM medium (containing 3 μM of Phellinus linteus polysaccharide) to encourage adhesion and growth. The culture environment was maintained at 37°C and 5% CO2 for 48 hours, after which the medium was replaced to remove non-adherent cells. When the cells reached 80% confluence, they were passaged to obtain third-generation antler mesenchymal stem cells (antler MSCs) for subsequent experiments.

[0041] Healthy antler MSCs were cultured for 48 hours in exosome-free medium, and the cell culture supernatant was collected in several hundred milliliters. Exosomes were purified by differential centrifugation: cells were removed by centrifugation at 300×g for 5 min; the supernatant was transferred and centrifuged at 2000×g for 20 min to remove cell debris and large vesicles; then centrifuged at 10000×g for 30 min to remove small impurities and microvesicles. The clarified supernatant was filtered through a 0.22 μm filter and then centrifuged at 100000×g for 70 min to precipitate the exosomes. The supernatant was carefully discarded, and the exosome precipitate was resuspended in pre-cooled PBS and centrifuged again at 100000×g for 70 min to improve purity. Finally, the exosome precipitate was resuspended in an appropriate amount of PBS (volume depends on the precipitate size, generally several hundred microliters) to obtain a high-purity antler MSCs exosome suspension.

[0042] Example 2 In this embodiment, the preparation and extraction of the deer antler stem cell exosomes can be carried out using existing culture methods.

[0043] In this embodiment, fresh antler tissue from healthy sika deer was selected, and mesenchymal tissue was obtained under aseptic conditions. The antler tissue was cut into small pieces (approximately 2 mm in size) and placed in a digestive solution containing 1% type I collagenase. Digestion was carried out at 37°C for 1 hour, with gentle agitation intermittently to release cells. After digestion, a single-cell suspension was obtained by filtration through a cell filter. The digestive enzymes were removed by centrifugation, and the cells were resuspended in PBS. Cells were seeded in culture dishes and cultured in serum-free DMEM medium (containing 2 μM of Phellinus linteus polysaccharide) to encourage adhesion and growth. The culture environment was controlled at 35°C and 5% CO2 for 48 hours, after which the medium was replaced to remove non-adherent cells. When the cells reached 80% confluence, they were passaged to obtain fourth-generation antler mesenchymal stem cells (antler MSCs) for subsequent experiments.

[0044] Healthy antler MSCs were cultured for 60 hours in exosome-free medium, and the cell culture supernatant was collected in several hundred milliliters. Exosomes were purified by differential centrifugation: cells were removed by centrifugation at 300×g for 5 min; the supernatant was transferred and centrifuged at 2000×g for 20 min to remove cell debris and large vesicles; then centrifuged at 10000×g for 30 min to remove small impurities and microvesicles. The clarified supernatant was filtered through a 0.22 μm filter and then centrifuged at 100000×g for 70 min to precipitate the exosomes. The supernatant was carefully discarded, and the exosome precipitate was resuspended in pre-cooled PBS and centrifuged again at 100000×g for 70 min to improve purity. Finally, the exosome precipitate was resuspended in an appropriate amount of PBS (volume depends on the precipitate size, generally several hundred microliters) to obtain a high-purity antler MSCs exosome suspension.

[0045] Example 3 In this embodiment, the preparation and extraction of the deer antler stem cell exosomes can be carried out using existing culture methods.

[0046] In this embodiment, fresh antler tissue from healthy sika deer was selected, and mesenchymal tissue was obtained under aseptic conditions. The antler tissue was cut into small pieces (approximately 2 mm in size) and placed in a digestive solution containing 1% type I collagenase. Digestion was carried out at 37°C for 0.5 hours, with gentle agitation intermittently to release cells. After digestion, a single-cell suspension was obtained by filtration through a cell filter. The digestive enzymes were removed by centrifugation, and the cells were resuspended in PBS. Cells were seeded in culture dishes and cultured in serum-free DMEM medium (containing 3 μM of Phellinus linteus polysaccharide) to encourage adhesion and growth. The culture environment was controlled at 37°C and 5% CO2 for 36 hours, after which the medium was replaced to remove non-adherent cells. When the cells reached 80% confluence, they were passaged to expand the cell line into third-generation antler mesenchymal stem cells (antler MSCs) for subsequent experiments.

[0047] Healthy antler MSCs were cultured for 48 hours in exosome-free medium, and the cell culture supernatant was collected in several hundred milliliters. Exosomes were purified by differential centrifugation: cells were removed by centrifugation at 300×g for 5 min; the supernatant was transferred and centrifuged at 2000×g for 20 min to remove cell debris and large vesicles; then centrifuged at 10000×g for 30 min to remove small impurities and microvesicles. The clarified supernatant was filtered through a 0.22 μm filter and then centrifuged at 100000×g for 70 min to precipitate the exosomes. The supernatant was carefully discarded, and the exosome precipitate was resuspended in pre-cooled PBS and centrifuged again at 100000×g for 70 min to improve purity. Finally, the exosome precipitate was resuspended in an appropriate amount of PBS (volume depends on the precipitate size, generally several hundred microliters) to obtain a high-purity antler MSCs exosome suspension.

[0048] Example 4 This embodiment uses dodder seed to prepare and extract exosomes.

[0049] Fresh dodder seeds were rinsed with deionized water to remove surface contaminants. After draining, the seeds were flash-frozen in liquid nitrogen and ground into a fine powder. The powder was then homogenized in pre-cooled PBS buffer at 4°C using a tissue homogenizer to obtain a homogenate. This homogenate was then centrifuged at 1000×g for 20 minutes at 4°C to remove any undisturbed plant tissue and large debris. The supernatant was carefully transferred to a new centrifuge tube, taking care to avoid aspirating any precipitate.

[0050] The supernatant was centrifuged at 4°C and 15000×g for 40 minutes to remove large organelles (such as mitochondria and chloroplast fragments) and large microvesicles. The supernatant was then filtered through a 0.22 μm microporous membrane to remove all particles larger than 220 nm, ensuring the purity of the sample after subsequent ultrafiltration.

[0051] Transfer the filtered supernatant into matching ultracentrifuge tubes, ensuring equilibration (weight difference <0.01g). Centrifuge at 120,000 × g for 90 minutes at 4°C. The exosomes will precipitate at the bottom of the ultracentrifuge tube. Carefully discard the supernatant and collect the precipitate at the bottom of the tube. Resuspend the final precipitate (cuscutellaria exosomes) in 100-200 μL of PBS or sterile saline, and store on ice for later use or aliquot and store at -80°C for long-term storage.

[0052] Example 5 Fresh dodder seeds were rinsed with deionized water to remove surface contaminants. After draining, the seeds were flash-frozen in liquid nitrogen and ground into a fine powder. The powder was then homogenized in pre-chilled PBS buffer at 4°C using a tissue homogenizer to obtain a homogenate. This homogenate was then centrifuged at 300×g for 30 minutes at 4°C to remove any undisturbed plant tissue and large debris. The supernatant was carefully transferred to a new centrifuge tube, taking care to avoid aspirating any precipitate.

[0053] The supernatant was centrifuged at 4°C and 10,000 × g for 60 minutes to remove large organelles (such as mitochondria and chloroplast fragments) and large microvesicles. The supernatant was then filtered through a 0.22 μm microporous membrane to remove all particles larger than 220 nm, ensuring the purity of the sample after subsequent ultrafiltration.

[0054] Transfer the filtered supernatant into matching ultracentrifuge tubes, ensuring equilibration (weight difference <0.01g). Centrifuge at 4°C and 100,000 × g for 120 minutes. Exosomes will precipitate at the bottom of the ultracentrifuge tube. Carefully discard the supernatant and collect the precipitate. Resuspend the final precipitate (cuscutellaria exosomes) in 100-200 μL of PBS or sterile saline, and store on ice for later use or aliquot and store at -80°C for long-term storage.

[0055] Example 6 Fresh dodder seeds were rinsed with deionized water to remove surface contaminants. After draining, the seeds were flash-frozen in liquid nitrogen and ground into a fine powder. The powder was then homogenized in pre-cooled PBS buffer at 4°C using a tissue homogenizer to obtain a homogenate. This homogenate was then centrifuged at 2000×g for 10 minutes at 4°C to remove any undisturbed plant tissue and large debris. The supernatant was carefully transferred to a new centrifuge tube, taking care to avoid aspirating any precipitate.

[0056] The supernatant was centrifuged at 4°C and 20,000 × g for 30 minutes to remove large organelles (such as mitochondria and chloroplast fragments) and large microvesicles. The supernatant was then filtered through a 0.22 μm microporous membrane to remove all particles larger than 220 nm, ensuring the purity of the sample after subsequent ultrafiltration.

[0057] Transfer the filtered supernatant into matching ultracentrifuge tubes, ensuring equilibration (weight difference <0.01g). Centrifuge at 4°C and 150,000 × g for 60 minutes. Exosomes will precipitate at the bottom of the ultracentrifuge tube. Carefully discard the supernatant and collect the precipitate at the bottom of the tube. Resuspend the final precipitate (cuscutellaria exosomes) in 100-200 μL of PBS or sterile saline, and store on ice for later use or aliquot and store at -80°C for long-term storage.

[0058] Example 7 The stem cell exosomes described in this embodiment are a mixture of the deer antler stem cell exosomes prepared in Example 1 and the dodder exosomes prepared in Example 4, wherein the mass ratio of the deer antler stem cell exosomes to the dodder exosomes is 2:1.

[0059] Example 8 The stem cell exosomes described in this embodiment are a mixture of the deer antler stem cell exosomes prepared in Example 2 and the dodder seed exosomes prepared in Example 5, wherein the mass ratio of the deer antler stem cell exosomes to the dodder seed exosomes is 2:1.

[0060] Example 9 The stem cell exosomes described in this embodiment are a mixture of the deer antler stem cell exosomes prepared in Example 3 and the dodder seed exosomes prepared in Example 6, wherein the mass ratio of the deer antler stem cell exosomes to the dodder seed exosomes is 2:1.

[0061] Comparative Example 1 The preparation method of stem cell exosomes in this comparative example is the same as that in Example 1, except that the serum-free culture medium does not contain the Phellinus linteus polysaccharide.

[0062] Experimental Example This embodiment tests the uric acid-lowering effects of the exosomes prepared in Examples 1, 4, and 7 above.

[0063] In this experimental example, the effect of exosomes on lowering uric acid was determined according to the method disclosed in Chinese Patent CN112189505A.

[0064] Seventy male SPF mice (25±2g) were randomly divided into seven groups: normal control group, hyperuricemia model control group, positive control group, experimental group 1, experimental group 2, experimental group 3 and experimental group 4.

[0065] Except for the normal control group, which received intraperitoneal injection and oral administration of normal saline, other groups received intraperitoneal injection of potassium oxonate at a dose of 100 mg / kg / day, and simultaneously administered hypoxanthine at a dose of 600 mg / kg / day by oral administration to induce modeling. One hour before modeling, fasting was allowed, but water was permitted. One hour after modeling, the positive control group received oral administration of allopurinol at a dose of 5 mg / kg / day; experimental group 1 received oral administration of exosome extract prepared in Example 1 at a dose of 100 mg / kg / day; experimental group 2 received oral administration of exosome extract prepared in Example 4 at a dose of 100 mg / kg / day; experimental group 3 received oral administration of exosome extract prepared in Example 7 at a dose of 100 mg / kg / day; experimental group 4 received oral administration of exosome extract prepared in Comparative Example 1 at a dose of 100 mg / kg / day; and the normal control group and the hyperuricemia model control group received the same volume of normal saline by oral administration for 7 consecutive days.

[0066] One hour after administration of the drug via gavage on day 7, the patient was anesthetized and the eyeballs were enucleated to collect blood. The serum was separated by centrifugation at 3500 r / min for 10 min, and the uric acid concentration in the serum was measured. The results are shown in Table 1 below.

[0067] Table 1. Results of the test on the uric acid-lowering effect of exosome extracts

[0068] As can be seen from the data in Table 1 above, the deer antler stem cell exosomes prepared in this invention, when induced by the addition of Phellinus linteus polysaccharide, can exhibit uric acid-lowering activity, showing a significant uric acid-lowering performance compared to deer antler stem cell exosomes cultured alone. Similarly, the present invention also found that exosomes extracted from Cuscuta chinensis possess certain uric acid-lowering properties, although their activity does not reach the level of the positive control, they still have good development potential.

[0069] The stem cell exosomes of the present invention are obtained by combining the deer antler stem cell exosomes and dodder seed exosomes to form an exosome composition. The uric acid-lowering activity of the two is further enhanced to achieve a synergistic effect, effectively enhancing the potential effect of treating gout.

[0070] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing stem cell exosomes, characterized in that, Includes the following steps: (1) Deer antler tissue was taken and deer antler mesenchymal stem cells were obtained; (2) The isolated deer antler mesenchymal stem cells were added to a serum-free culture medium containing Phellinus linteus polysaccharide for amplification culture; (3) Collect the culture and extract the exosomes to obtain deer antler stem cell exosomes.

2. The method for preparing stem cell exosomes according to claim 1, characterized in that, In step (1), the separation step of the deer antler mesenchymal stem cells includes the step of adding the deer antler tissue to a digestive solution for digestion, and the step of obtaining the deer antler mesenchymal stem cells by filtration and centrifugation.

3. The method for preparing stem cell exosomes according to claim 1, characterized in that, In step (2), the concentration of the Sanghuang polysaccharide in the serum-free culture medium is 2-3 μM.

4. The method for preparing stem cell exosomes according to claim 3, characterized in that, In step (2), the parameters of the amplification step include: culture temperature of 35-37℃, culture at 5% v / v CO2 for 36-60h.

5. The method for preparing stem cell exosomes according to claim 1, characterized in that, In step (3), the exosome extraction step includes: taking the culture, performing solid-liquid separation and collecting the supernatant, and obtaining deer antler stem cell exosomes after impurity removal, filtration, centrifugation and washing.

6. The method for preparing stem cell exosomes according to any one of claims 1-5, characterized in that, Step (3) further includes adding dodder exosomes to the deer antler stem cell exosomes for mixing, so as to obtain the desired stem cell exosomes.

7. The method for preparing stem cell exosomes according to claim 6, characterized in that, The mass ratio of the deer antler stem cell exosomes to the dodder seed exosomes is 1-3:

1.

8. The method for preparing stem cell exosomes according to claim 7, characterized in that, The preparation steps of the dodder exosomes include: The dodder tissue was mixed with pre-cooled PBS phosphate buffer at low temperature and ground thoroughly to form a homogenate. After preliminary filtration, the initial filtrate was obtained. Centrifuge the initial filtrate at 300-2000×g for 10-30 minutes and collect the first supernatant; Continue to centrifuge the first supernatant at 10,000-20,000 × g for 30-60 minutes, and collect the second supernatant; Continue to centrifuge the second supernatant at 100,000-150,000×g for 60-120 minutes, discard the supernatant and collect the precipitate; The precipitate was then washed with PBS phosphate buffer to obtain the final product.

9. A stem cell exosome, characterized in that, It is prepared by the method described in any one of claims 1-8.

10. Use of the stem cell exosomes of claim 9 for the preparation of medicaments for treating gout or lowering uric acid.

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