RNA particle complex, and preparation method therefor and use thereof

Abstract

An RNA particle complex, and a preparation method therefor and a use thereof. The RNA particle complex comprises RNA and carbonate apatite particles. The preparation method comprises the following steps: S1. adding 300 ug of RNA, 440 mM of NaHCO3, 9 mM of NaH2PO4, and 58 mM of CaCl2 to prepare 100 mL of an aqueous solution containing a mixture of RNA and inorganic ions; and S2. stirring at 20°C for 3 minutes, and then centrifuging at 4,000 rpm for 3 minutes to obtain a precipitate, i.e., the RNA particle complex. The present invention also relates to a use of the RNA particle complex in a drug or a daily chemical for treating dermatitis and promoting skin wound healing. The use of the RNA particle complex in a skin drug or a daily chemical can significantly improve the therapeutic effect on skin wound healing and effectively prevent scar formation caused by skin wounds.

Description

RNA particle complex, preparation method and application thereof Technical Field

[0001] The present invention relates to the field of biomedicine technology, and in particular to an RNA particle complex, a preparation method and applications thereof. Background Art

[0002] RNA, short for ribonucleic acid, is the carrier of genetic information found in biological cells, as well as some viruses and viroids. Composed of at least several dozen ribonucleotides linked by phosphodiester bonds, it is named for the sugar ribose. RNA is ubiquitous in animals, plants, microorganisms, and certain viruses and bacteriophages. RNA is closely linked to protein biosynthesis. In RNA viruses and bacteriophages, RNA is the carrier of genetic information.

[0003] Existing technologies, such as Chinese patent publication number CN108697653B, disclose wound management and treatment following injury and promoting tissue regeneration. Specifically, it relates to a conjugate of miRNA-146a and nano-cerium oxide for improving wound healing and, in some embodiments, preventing adverse ventricular remodeling after myocardial infarction.

[0004] Although miRNA-146a has been shown to have anti-dermatitis and wound healing effects, there are no commercial products using miRNA-146a as a primary ingredient in dermatological medications or daily cosmetics. The reasons are as follows: 1. miRNA is easily degraded; 2. The active ingredient has low skin penetration; and 3. There are no large-scale RNA delivery vectors that are effective in the skin.

[0005] Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide an RNA particle complex, a preparation method and application thereof. The application of this RNA particle complex in skin medicines or daily chemical products can significantly improve the therapeutic effect on skin wound healing and effectively prevent scar formation caused by skin trauma.

[0007] The above-mentioned object of the present invention is achieved through the following technical solutions:

[0008] An RNA particle complex comprising RNA and carbonate apatite particles.

[0009] In a preferred embodiment of the present invention, the mass percentage of the RNA is 0.005% to 1.5%, and the mass percentage of the carbonate apatite particles is 98.5% to 99.995%.

[0010] In a preferred embodiment of the present invention, the mass percentage of the RNA is 1.5% to 5%, and the mass percentage of the carbonate apatite particles is 95% to 98.5%.

[0011] In a preferred embodiment of the present invention, the mass percentage of the RNA is 5% to 15%, and the mass percentage of the carbonate apatite particles is 85% to 95%.

[0012] In a preferred embodiment of the present invention, the RNA is any one or a combination of microRNA (miRNA), siRNA, messenger RNA (mRNA), long non-coding RNA (lncRNA), piRNA, and snoRNA.

[0013] The present invention also provides a method for preparing the above-mentioned RNA particle complex, comprising the following steps:

[0014] S1. preparing an aqueous solution containing a mixture of RNA and inorganic ions;

[0015] S2. Stirring the aqueous solution until uniform, and then centrifuging to obtain a precipitate, which is the RNA particle complex.

[0016] Optionally, a method for preparing the RNA particle complex is provided, comprising the following steps:

[0017] S1. Add 300 μg of RNA, 440 mM NaHCO 3 , 9 mM NaH 2 PO 4 , and 58 mM CaCl 2 to prepare 100 mL of an aqueous solution containing a mixture of RNA and inorganic ions.

[0018] S2. After stirring at 20° C. for 3 minutes, centrifuge at 4000 rpm for 3 minutes. The resulting precipitate is the RNA particle complex.

[0019] In a preferred embodiment of the present invention, in step S1, the inorganic ion mixture includes Ca 2+ 、CO3 2+ PO4 3- 、Na + 、CI - .

[0020] Optionally, the inorganic ion mixture includes carbonate apatite particles.

[0021] In one embodiment of the present invention, the RNA particle complex or the RNA particle complex prepared by the above preparation method is provided for use in treating dermatitis.

[0022] In one embodiment of the present invention, the RNA particle complex described above or the RNA particle complex prepared by the above preparation method is provided for promoting skin wound healing.

[0023] In one embodiment of the present invention, the RNA particle complex or the RNA particle complex prepared by the above preparation method is provided for use in daily chemical products.

[0024] The present invention also provides a drug for treating dermatitis, which comprises the RNA particle complex or the RNA particle complex prepared by the above preparation method.

[0025] The present invention also provides a drug for promoting skin wound healing, which comprises the RNA particle complex or the RNA particle complex prepared by the above preparation method.

[0026] The present invention also provides a medicine for daily chemical products, which comprises the RNA particle complex or the RNA particle complex prepared by the above preparation method.

[0027] The present invention also provides use of the RNA particle complex or the RNA particle complex prepared by the above preparation method in preparing a drug for treating dermatitis.

[0028] The present invention also provides use of the RNA particle complex or the RNA particle complex prepared by the above preparation method in preparing a drug for promoting skin wound healing.

[0029] The present invention also provides the use of the RNA particle complex or the RNA particle complex prepared by the above preparation method in the preparation of daily chemical products.

[0030] The present invention also provides a method for treating dermatitis, comprising administering an effective amount of the above-mentioned RNA particle complex or the RNA particle complex prepared by the above-mentioned preparation method to a subject in need thereof.

[0031] The present invention also provides a method for promoting skin wound healing, comprising administering an effective amount of the above-mentioned RNA particle complex to a subject in need thereof.

[0032] As a preferred embodiment of the present invention, the application of the RNA particle complex in skin medications or daily chemicals can significantly enhance the therapeutic effect on skin wound healing and effectively prevent scar formation caused by skin trauma, including superficial burns and deeper skin wounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a schematic diagram of the RNA particle complex.

[0034] FIG2 is a schematic diagram showing the material stability of RNA (miRNA146a-5p 50 ug) and RNA particle complex (containing miRNA146a-5p 50 ug) in mouse serum.

[0035] FIG3 is a diagram showing the modeling of allergic dermatitis in Experimental Example 1.

[0036] FIG4 is a diagram showing the recovery of dermatitis on the back of mice in Experimental Example 1.

[0037] FIG5 is a statistical representation of the skin lesion scores on Day 0 and Day 4 in Experimental Example 1.

[0038] FIG6 is a line chart showing the changes in the dermatitis lesion scores in Experimental Example 1. ...

[0039] FIG7 is a HE staining analysis of the dermatitis pathology of mice in Experimental Example 1.

[0040] FIG8 is a schematic diagram showing the healing of full-thickness skin injuries on the back of mice in Experimental Example 2.

[0041] FIG9 is a statistical chart showing the skin wound healing evaluation on Day 15 in Experimental Example 2.

[0042] FIG10 is a HE staining analysis of the dermatitis pathology of mice in Experimental Example 2.

[0043] FIG11 is a graph showing the immunohistochemical expression of Collagen-1 in Experimental Example 2.

[0044] FIG12 is an immunohistochemical expression diagram of FGF-2 in Experimental Example 2. DETAILED DESCRIPTION

[0045] The present invention is exemplified below by specific examples. It should be understood by those skilled in the art that the following examples are merely to help understand the present invention and should not be regarded as limiting the scope of the present invention.

[0046] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0047] Unless otherwise specified, the "content" in the present invention is calculated by weight. For those skilled in the art, the specific meanings of the above terms in this application can be understood by those skilled in the art.

[0048] miRNA146a: MicroRNA (miR)-146a regulates autoimmunity, inflammation, and keratinocyte proliferation, and is involved in the pathology of psoriasis (Shen, H., et al., J Clin Lab Anal, 2022. 36(2): p.e24198.). In human primary keratinocytes, miR-146a inhibits the expression of many proinflammatory cytokines, including CCL5 and IL-8 (Meisgen, F., et al., J Invest Dermatol, 2014. 134(7): p.

[0049] 1931-1940; Rebane, A., et al., J Allergy Clin Immunol, 2014. 134(4): p.836-847e11). miR-146a has been shown to function as an anti-inflammatory miRNA in mouse models of atopic dermatitis[3], irritant contact dermatitis[4], and psoriasis[5] (Rebane, A., et al., J Allergy Clin Immunol, 2014. 134(4): p.836-847e11; Urgard, E., et al., J Control Release, 2016. 235: p.195-204; Srivastava, A., et al., J Allergy Clin Immunol, 2017. 139(2): p.550-561). At the same time, miR-146a plays an important role in diabetic wound healing by regulating pro-inflammatory gene expression. Mesenchymal stem cell therapy can regulate miR-146a levels to reduce wound inflammation and enhance wound closure (Xu, J., et al., Diabetes, 2012. 61(11): p. 2906-12). Engineered exosomes loaded with miR-146a target IRAK1 to promote diabetic wound healing (Li, Q., et al., Signal Transduct Target Ther, 2023. 8(1): p. 62).

[0050] Nanoparticle RNA delivery system: In 2015, the inventor Wu Xin et al. first reported a novel nanoparticle system, super carbonate apatite composed of inorganic ions, as an intravenous in vivo delivery system for siRNA / miRNA (Wu, X., et al., PLoS One, 2015.10(3): p.e0116022). Subsequently, the application of this system in several mouse models of siRNA or miRNA-based cancer treatment methods was reported (Takeyama, H., et al., Mol Cancer Ther, 2014.13(4): p.976-85; Takahashi, H., et al., Mol Cancer Ther, 2015.14(7): p.1705-16; Ogawa, H., et al., PLoS One, 2015.10(5): p.e0127119; Hiraki, M., et al., Mol Ther Nucleic Acids, 2015.4: p.e231; Inoue, A., et al., Mol Cancer Ther, 2018.17(5): p.977-987; Morimoto, Y., et al., Br J Cancer, 2020.122(7): p.1037-1049). In addition to cancer treatment, sCA also systemically delivers miRNA to inflammatory lesions in the body to treat inflammatory colitis (Fukata, T., et al., Mol Ther Nucleic Acids, 2018.12: p.658-671). Local delivery of sCA containing plasmid DNA or siRNA to skin wounds can accelerate wound healing and reduce scar formation, which proves an effective method for treating stubborn abnormal scars (Aoki, M., et al., Int J Mol Sci, 2019.20(14); Aoki, M., et al., Mol Ther Nucleic Acids, 2020.22: p.50-61). Skin tissue penetrating micron particle complex: After continuous improvements, Wu Xin developed a micron particle complex for use in medicines or daily chemical products. It can carry bamboo sap essence, increase skin permeability, and has significant hair growth effects (application number: CN202310728235.1, June 20, 2023), anti-dermatitis effects (application number: CN202310985360.0, August 7, 2023) and skin wound healing effects (application number: CN202310985076.3, August 7, 2023).

[0051] Implementation Plan 1:

[0052] Referring to Figure 1 , one embodiment of the RNA particle complex of the present invention includes RNA and carbonate apatite particles. The mass percentage of RNA is 0.005% to 1.5%, and the mass percentage of carbonate apatite particles is 98.5% to 99.995%. In this embodiment, the mass percentage of RNA is preferably 0.005%, and the mass percentage of carbonate apatite particles is preferably 99.995%.

[0053] In this embodiment, the RNA is any one of microRNA (miRNA), siRNA, messenger RNA (mRNA), long non-coding RNA (lncRNA), piRNA, and snoRNA, or a combination thereof.

[0054] Implementation Plan 2:

[0055] In one embodiment of the RNA particle complex of the present invention, the complex comprises RNA and carbonate apatite particles, wherein the mass percentage of RNA is 1.5% to 5% and the mass percentage of carbonate apatite particles is 95% to 98.5%.

[0056] In this embodiment, the RNA is any one or a combination of microRNA (miRNA), siRNA, messenger RNA (mRNA), long non-coding RNA (lncRNA), piRNA, and snoRNA.

[0057] Implementation Plan 3:

[0058] In one embodiment of the RNA particle complex of the present invention, the complex comprises RNA and carbonate apatite particles, wherein the mass percentage of RNA is 5% to 15% and the mass percentage of carbonate apatite particles is 85% to 95%.

[0059] In this embodiment, the RNA is any one or a combination of microRNA (miRNA), siRNA, messenger RNA (mRNA), long non-coding RNA (lncRNA), piRNA, and snoRNA.

[0060] Implementation Plan 4:

[0061] The method for preparing the RNA particle complex according to the first embodiment of the present invention may include the following steps:

[0062] S1. Add 300 μg of RNA (miRNA146a-5p), 440 mM NaHCO 3 , 9 mM NaH 2 PO 4 , and 58 mM CaCl 2 to prepare 100 mL of an aqueous solution containing a mixture of RNA and inorganic ions.

[0063] S2. After stirring at 20°C for 3 minutes, centrifuge at 4000 rpm for 3 minutes. The resulting precipitate is the RNA particle complex.

[0064] Wherein, in step S1, the inorganic ion mixture includes Ca 2+ PO3 2+ PO4 3- 、Na + 、CI - .

[0065] 2 , the material stability of RNA (miRNA-146a-5p 50 ug) and RNA particle complex (containing miRNA-146a-5p 50 ug) in mouse serum. When incubated in mouse serum at 37° C., RNA was degraded to approximately 20% of the original amount within only 10 minutes.

[0066] Implementation Plan 5:

[0067] The RNA particle complex of embodiment 1 is used in the treatment of dermatitis.

[0068] Implementation Plan 6:

[0069] Use of the RNA particle complex of embodiment 1 in a drug for promoting skin wound healing.

[0070] Implementation Plan 7:

[0071] Application of the RNA particle complex of embodiment 1 in daily chemical products.

[0072] In Experimental Example 1 and Experimental Example 2, the present invention is further described with reference to FIG3 to FIG12:

[0073] The HE staining method can be a conventional method in the art. As an example, the HE staining experimental process is as follows:

[0074] Slice → bake → dewax and hydrate → stain → examine under a microscope.

[0075] The experimental steps of HE staining are as follows:

[0076] 1. Paraffin Sectioning: Dehydrate fixed tissue samples in 75%, 85%, 95% I, 95% II, 100% I, and 100% II ethanol solutions for 60 minutes each, clear in xylene I and II for 45 minutes each, then permeabilize in paraffin I, paraffin II, and paraffin III for 50-60 minutes each. Embed in paraffin and section.

[0077] 2. Dewax the paraffin sections to water: bake the paraffin sections, then place the sections in xylene I for 10 minutes, xylene II for 10 minutes, anhydrous ethanol I for 3 minutes, anhydrous ethanol II for 3 minutes, 95% alcohol for 3 minutes, 80% alcohol for 3 minutes, and pure water for 2 minutes.

[0078] 3. Hematoxylin staining: Stain in hematoxylin solution for 3-5 minutes, wash with tap water, differentiate with 1% hydrochloric acid alcohol, wash with tap water, return to blue with bluing solution, and rinse with running water.

[0079] 4. Eosin staining: Stain the sections in eosin solution for 3-5 minutes and rinse with running water.

[0080] 5. Dehydration and sealing: Put the slices into 80%, 95%, 100% I and 100% II ethanol solutions in sequence for rapid dehydration, and seal the slices with ultra-clean high-grade sealing glue.

[0081] 6. Microscope examination: image acquisition.

[0082] Staining results: cell nuclei appear blue and cytoplasm appears red.

[0083] The immunohistochemical detection method can be a conventional method in the art. As an example, a paraffin section immunohistochemical assay can be used, and the process is as follows:

[0084] Paraffin-embedded sections → baking → dewaxing and hydration → antigen retrieval → elimination of endogenous peroxidase → blocking → primary antibody incubation → secondary antibody incubation → DBA color development → counterstaining → dehydration and clearing → sealing → microscopic examination.

[0085] 1. Paraffin Sectioning: Dehydrate fixed tissue samples in 75%, 85%, 95% I, 95% II, 100% I, and 100% II ethanol solutions for 60 minutes each, clear in xylene I and II for 45 minutes each, then permeabilize in paraffin I, paraffin II, and paraffin III for 50-60 minutes each. Embed in paraffin and section.

[0086] 2. Dewax the paraffin sections to water: bake the paraffin sections, then place the sections in xylene I for 10 minutes, xylene II for 10 minutes, anhydrous ethanol I for 3 minutes, anhydrous ethanol II for 3 minutes, 95% alcohol for 3 minutes, 80% alcohol for 3 minutes, and pure water for 2 minutes.

[0087] 3. Antigen retrieval of sections: High-pressure retrieval (place the sections in a retrieval box, add antigen retrieval solution (citrate buffer), heat the pressure cooker until it automatically releases gas, remove from the heat source after 2 minutes and allow to cool naturally, discard the antigen retrieval solution, and rinse the sections with PBS.)

[0088] 4. Eliminate endogenous peroxidase: Move the slices into a humidified chamber and add freshly prepared 3% hydrogen peroxide to remove endogenous peroxidase blocking solution.

[0089] Incubate at room temperature for 10 min and rinse thoroughly with PBS.

[0090] 5. Non-specific blocking: Wash the slides with PBS three times, 5 minutes each time, dry the PBS around the tissue with absorbent paper, add 5% BSA on the slides, and block at 37°C for 30 minutes.

[0091] 6. Apply primary antibody: Use absorbent paper to absorb the blocking solution around the tissue, without washing, and add enough diluted antibody to each slide.

[0092] Primary antibodies: VEGF (1 / 100), IGF-1 (1 / 100), placed in a humidified chamber, incubated overnight at 4°C.

[0093] 7. Apply secondary antibody: Take out the wet box that was incubated overnight at 4°C, let it stand at room temperature for 45 minutes, rinse the slides with PBS three times, 5 minutes each time, add horseradish enzyme-labeled goat anti-rabbit IgG (H+L) (1:100), incubate at 37°C for 30 minutes, and rinse thoroughly with PBS.

[0094] 8. Color development and counterstaining: DAB color development for 3-5 minutes, monitor the degree of staining under a microscope, rinse with PBS or tap water for 1 minute, counterstain with hematoxylin for 3 minutes, differentiate with hydrochloric acid and alcohol, return to blue, and rinse with tap water.

[0095] 9. Dehydration and transparency: Put the sections into 80%, 95%, 100% I and 100% II ethanol solutions in sequence for rapid dehydration. Transparentize with xylene I and II. Seal the sections with neutral resin glue and examine under a microscope.

[0096] Description of staining results: Hematoxylin stains the cell nucleus in blue, and DAB stains the positive expression in brown.

[0097] Experimental Example 1:

[0098] 1. Introduction to allergic dermatitis modeling:

[0099] As shown in Figure 3, mice were depilated to remove back hair and induced with DNCB (2,4-dinitrochlorobenzene) to establish the model. On day 1, 2% DNCB solution was administered (150 μL) to the back and 10 μL behind the ear for initial sensitization. On days 5, 7, 9, 11, 13, 16, 18, 20, 22, and 24, 0.5% DNCB solution was administered (150 μL) to the back and 10 μL behind the ear for challenge. On day 25, the model was evaluated by pathological section analysis, skin lesion scoring, and scratching test. Mice with a total score of 5 or higher were considered successfully established.

[0100] Pathological sections showed that under an optical microscope, the skin tissue structure of the control group was normal with no obvious pathological changes; while the stratum corneum of the skin tissue of the model group was keratinized, the epidermis was significantly thickened, and the dermis was infiltrated with inflammatory cells.

[0101] 2. Experimental study on the therapeutic effect of RNA particle complexes on DNCB-induced dermatitis in mice:

[0102] Experimental mice: C57BL / 6 male mice, 6 weeks old;

[0103] Experimental environment: temperature 20-26°C, humidity 40%-70%;

[0104] Experimental groups: The experiment was divided into 3 groups, 4 mice in each group;

[0105] 1) RNA (2 sprays / animal / day), an aqueous solution containing RNA, i.e., the RNA content used in step S1 of the fourth embodiment for preparing RNA particle complexes;

[0106] 2) RNA particle complex (spray twice / mouse / day), sprayed by dissolving the precipitate obtained in step S2 of the fourth embodiment above in 50 mL of distilled water;

[0107] 3) Apatite aqueous solution (spray twice / animal / day). Apatite is carbonated apatite. 440 mM NaHCO₃, 9 mM NaH₂PO₄, and 58 mM CaCl₂ are added to water to make a total of 100 mL of the solution. The solution is stirred at 20°C for 3 minutes, centrifuged at 4000 rpm for 3 minutes, and the resulting precipitate is dissolved in 50 mL of distilled water.

[0108] Animal Modeling: After all animals were acclimated to the animal house, the back hair of the mice was removed by depilation and the model was induced with DNCB. On day 1, 2% DNCB solution was administered at a dose of 150 μL on the back and 10 μL behind the ear for initial sensitization. On days 5, 7, 9, 11, 13, 16, 18, 20, 22, and 24, 0.5% DNCB solution was administered at a dose of 150 μL on the back and 10 μL behind the ear for challenge. On day 25, the model was evaluated by skin lesion scoring and scratching test. Mice with a total score of 5 or higher were considered to have successfully established the model.

[0109] Treatment Procedure: On Day 0, each group of animals received the corresponding medication. Two sprays of medication were applied to the lesions according to group until sacrifice. The back skin was photographed and observed every two days starting on the day of medication administration and on days 2, 4, 6, and 8. After the observation period, the mice in each group were sacrificed and tissue from the lesions was obtained. The tissue was fixed with fixative and then stained with HE staining.

[0110] The recovery of dermatitis on the back of mice is shown in Figure 4:

[0111] The statistical table of skin lesion scores on Day 0 and Day 4 is shown in Figure 5. The skin lesion score is divided into four parts: edema, hemorrhage, scaling and excoriation, and each part is scored according to the severity level: 0-asymptomatic, 1-mild, 2-intermediate, and 3-severe.

[0112] Figure 6 shows a line graph of the changes in dermatitis lesion scores in mice, and Figure 6 shows the total inflammation score on Day 4. The RNA particle complex treatment group demonstrated a significant anti-inflammatory effect compared to the RNA and apatite treatment groups. Statistical values ​​are expressed as mean ± standard error. One-way ANOVA and Tukey's multiple comparisons test were used for statistical evaluation, with significance considered if P < 0.05.

[0113] Sampling: On day 8, skin tissue from the lower half of the mice was removed under anesthesia and sectioned for pathological HE staining analysis, as shown in Figure 7. Optical microscopy revealed hyperkeratosis with parakeratosis in the stratum corneum of the RNA and apatite-treated groups, along with a large infiltration of inflammatory cells in the dermis. Treatment with the RNA particle complex significantly reduced inflammatory cell infiltration in the dermis, improved keratinization in the stratum corneum, and thinned the epidermis.

[0114] Experimental Example 2:

[0115] Experimental environment: temperature 20-26°C, humidity 40%-70%;

[0116] Experimental groups: The experiment was divided into 3 groups, 4 mice in each group;

[0117] 1) RNA (2 sprays / animal / day), an aqueous solution containing RNA, i.e., the RNA content used in step S1 of the fourth embodiment for preparing RNA particle complexes;

[0118] 2) RNA particle complex (spray twice / animal / day), sprayed by dissolving the precipitate obtained in step S2 of the fourth embodiment of the above application scheme in 50 mL of distilled water;

[0119] 3) Apatite aqueous solution (spray twice / animal / day). Apatite is carbonated apatite. 440 mM NaHCO₃, 9 mM NaH₂PO₄, and 58 mM CaCl₂ are added to water to make a total of 100 mL of the solution. The solution is stirred at 20°C for 3 minutes, centrifuged at 4000 rpm for 3 minutes, and the resulting precipitate is dissolved in 50 mL of distilled water.

[0120] Animal modeling: On Day 0, the backs of the anesthetized animals were depilated. A full-thickness skin injury model was constructed in all groups except the normal group. A 10 mm × 10 mm square injury was constructed on the lower back of the mice. The drug was sprayed twice on each wound according to the group until the mice were killed.

[0121] The animals with wounds were photographed and observed starting from the day of modeling, and the wound conditions were photographed and observed every 2 days, that is, the wound conditions were photographed and observed once on the day of modeling and on the 2nd, 4th, 6th, 8th, 10th, 12th, 14th, 15th, 16th, 17th and 18th days after modeling. After the observation, the mice in each group were killed and the tissues of the injured sites were obtained. After fixation with fixative, pathological HE staining and immunohistochemistry were performed to detect the expression of Collagen-1 and FGF-2.

[0122] Experimental results and analysis:

[0123] The healing status of full-thickness skin injuries on the back of mice is shown in FIG8 .

[0124] As shown in Figure 9, skin wound healing was assessed on Day 15. The RNA particle complex-treated group demonstrated significant skin wound healing compared to the RNA and apatite groups. Statistical values ​​are presented as mean ± standard error. One-way ANOVA and Tukey's multiple comparisons test were used for statistical evaluation, with significance considered if P < 0.05.

[0125] The HE staining analysis of the mouse skin pathology is shown in Figure 10. In the RNA and apatite treatment groups, the model group showed keratinization of the stratum corneum, significant thickening of the epidermis, and infiltration of inflammatory cells in the dermis. After treatment with the RNA particle complex, the keratinization of the stratum corneum was significantly improved, the epidermis was significantly thinned, and the infiltration of inflammatory cells was reduced.

[0126] Immunohistochemical detection of collagen-1 expression is shown in Figure 11. Compared with the RNA and apatite groups, the RNA particle complex showed that the dermal cells expressed collagen-1.

[0127] As shown in FIG12 , the expression of FGF-2 detected by immunohistochemistry showed that the RNA particle complexes expressed FGF-2 in the dermal cells compared with the RNA and apatite groups.

[0128] Collagen is the most important component of the extracellular matrix. It is a polymer that makes up various extracellular matrix substances and plays the role of binding tissue in animal cells. It is also the most important structural protein in animal tissues. The reason why the skin is elastic is mainly because the collagen in the collagen fibers in the dermis forms the skin's support. As people age, work becomes busy and tiring, the secretion of collagen in the skin decreases, causing the delicate skin to become loose and dry, resulting in wrinkles and loss of radiance. Therefore, to maintain the youthful vitality of the skin, it is necessary to increase the collagen content in the skin.

[0129] FGF2 plays a positive pathophysiological role in tissue remodeling, bone health, and regeneration, such as repairing neuronal damage, healing skin wounds, protecting joints, and controlling hypertension. Currently, clinical trials for recombinant FGF2 protein therapy focus on restorative treatments for conditions such as oral health, periodontitis, tympanic membrane perforation, and age-related macular degeneration.

[0130] The above experimental results show that:

[0131] The RNA particle complex improves the therapeutic effect on skin wound healing and can effectively prevent scar formation caused by skin trauma, including surface burns and deep skin trauma.

Claims

1. An RNA particle complex, characterized in that Includes RNA and carbonate apatite particles.

2. The RNA particle complex according to claim 1, characterized in that The mass percentage of the RNA is 0.005% to 1.5%, and the mass percentage of the carbonate apatite particles is 98.5% to 99.995%.

3. The RNA particle complex according to claim 1, characterized in that The mass percentage of the RNA is 1.5% to 5%, and the mass percentage of the carbonate apatite particles is 95% to 98.5%.

4. The RNA particle complex according to claim 1, characterized in that The mass percentage of the RNA is 5% to 15%, and the mass percentage of the carbonate apatite particles is 85% to 95%.

5. The RNA particle complex according to any one of claims 1 to 4, characterized in that The RNA is any one or a combination of miRNA, siRNA, mRNA, lncRNA, piRNA, and snoRNA.

6. The method for preparing the RNA particle complex according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. preparing an aqueous solution containing a mixture of RNA and inorganic ions; S2. Stirring the aqueous solution until evenly mixed, and then centrifuging to obtain a precipitate, which is the RNA particle complex.

7. The method for preparing the RNA particle complex according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, add 300ug RNA, 440mM NaHCO3, 9mM NaH2PO4, and 58 mM CaCl2 to prepare 100 mL of an aqueous solution containing a mixture of RNA and inorganic ions; S2. After stirring at 20° C. for 3 minutes, centrifuge at 4000 rpm for 3 minutes. The resulting precipitate is the RNA particle complex.

8. The method for preparing the RNA particle complex according to claim 6 or 7, characterized in that: In step S1, the inorganic ion mixture includes Ca 2+ 、CO3 2+ PO4 3- 、Na + , CI - , optionally, the inorganic ion mixture includes carbonate apatite particles.

9. The RNA particle complex according to any one of claims 1 to 5 or the RNA particle complex prepared by the preparation method according to any one of claims 6 to 8, for use in treating dermatitis, promoting skin wound healing, or daily chemical products.

10. A daily chemical product or a medicine for treating dermatitis or promoting skin wound healing, comprising the RNA particle complex according to any one of claims 1 to 5 or the RNA particle complex prepared by the preparation method according to any one of claims 6 to 8.

11. A method for treating dermatitis or promoting skin wound healing, comprising administering to a subject in need thereof an effective amount of the RNA particle complex according to any one of claims 1 to 5 or the RNA particle complex prepared by the preparation method according to any one of claims 6 to 8.

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