Preparation Of Dihydroquercetin Composite Nanofiber Membrane And Its Mechanism To Promote Skin Repair

The skin is an important physiological organ that regulates the body’s balance and is recognized as the body’s primary line of defense against infection.A wound can be defined as a sharp injury that disrupts the normal anatomical relationship of tissue.Once the structure or function of the skin is defective,the body is vulnerable to microbial invasion and wound infection,which can delay wound healing and even endanger life.Wound healing restores damaged tissue to its original shape by acting on biomolecules and cellular matrix.Good wound management,including control of microbial infections,cleaning the wound environment,keeping away from foreign bodies,and selecting appropriate wound dressings.This is important for managing the many complications that can occur during wound healing.Therefore,maintaining a suitable wound environment for the body and promoting the healing of skin wounds is still an important issue in clinical treatment.Dihydroquercetin(DHQ),also known as Taxifolin(Tax),is a natural dihydroflavonol compound.It has high biological activity,such as protecting the liver and kidneys,anti-inflammatory,antibacterial and anti-diabetic,regulating enzyme activity,improving microcirculation,anti-tumour effects and treating arthritis.As a new food ingredient,it has been widely used in the food,pharmaceutical and cosmetic industries.In recent years,nano-fibre polymers prepared by electrostatic spinning have attracted much attention for their unique properties such as high specific surface area,high porosity,and controllable structure and function.The increasing interest in developing nanofibres for biomedical applications has stimulated the further development of drug-laden nanofibre films for tissue repair and wound dressings.Therefore,this study was conducted to develop an effective and safe chitosan/polyvinylpyrrolidone/dihydroquercetin composite nanofibre membrane(CPD)using electrostatic spinning technology and to evaluate the wound healing ability and therapeutic mechanism of CPD.Details of the study and the results are as follows:1、Preparation of dihydroquercetin composite nanofibrous membrane and its structure and properties characterizationIn this study,loaded DHQ nanofibre membranes were prepared using chitosan(CS)and polyvinylpyrrolidone(PVP)for application in promoting skin repair.The properties of the CPD composite nanofibre films were characterised by scanning electron microscopy,infrared spectroscopy,X-ray diffraction,thermal stability and water contact angle tests.The nanofibre-based dressing was closer to the extracellular matrix,providing a moist repair environment for the wound and accelerating wound healing.CPD also showed a better network structure,allowing controlled drug delivery in local space and time,increasing drug bioavailability.In addition,the free radical scavenging activity of the CPD composite plate nanofibre membrane was improved.In vitro antibacterial experiments also showed that CPD could inhibit bacteria such as Escherichia coli and Staphylococcus aureus more effectively.This has laid the foundation for the research of DHQ as a wound dressing.2、Study on the role of dihydroquercetin composite nanofiber film in protecting UVA-induced photodamage in Ha Ca T cellsUltraviolet UVA radiation can cause skin photodamage.In this study,CPD intervention could significantly improve the viability of Ha Ca T cells induced by UVA-induced photodamage,reduce the production of intracellular ROS,increase the viability and HYP level of SOD and GSH-Px,and reduce MDA production.CPD can reduce the fluorescence intensity of TNF-α,inhibit the expression of protein that down-regulates NF-κB,and reduce the production of IKBα,TNF-α,IL-1β,COX-2 and i NOS,indicating that CPD has obvious effective anti-inflammatory effect on UVA radiation in Ha Ca T cells.In addition,CPD can reduce the fluorescence intensity of Caspase-3,inhibit the protein expression of Caspase-3 and Caspase-9 and the production of Bax,promote the expression of Bcl-2,and then inhibit UVA-induced apoptosis of Ha Ca T cells.In conclusion,CPD treatment effectively protects Ha Cat cells from photodamage caused by ultraviolet radiation.3、Study on the effect of dihydroquercetin composite nanofiber film to promote wound skin repair in miceA mouse model of acute skin injury was constructed,and the drug was administered using CPD composite nanofiber film to determine the protective effect and mechanism of action on skin wounds.The results showed that CPD treatment increased the rate of wound healing in the skin of mice,and H&E and Masson staining showed that CPD significantly improved the pathological changes caused by skin injury.Also,immunofluorescence staining observed elevated expression of vascular endothelial growth factor(VEGF),platelet-endothelial cell adhesion molecule(CD31),and pan-keratin(Pan-Keratin).On the results of protein blotting,the drug-laden membrane could regulate both the expression of autophagy-related proteins PI3 K and AKT,m TOR and its phosphorylated proteins,and the expression of LC3II/I,Atg5,Atg7 and P62,suggesting that CPD could promote skin repair in mouse wounds by regulating the level of autophagy.4、Study on the role of dihydroquercetin composite nanofibrous membrane in regulating wound flora and promoting wound repair in miceIn this paper,the role of CPD in the regulation of traumatic flora was investigated by means of skin flora testing.It was found that CPD not only significantly increased the Shannon index,Simpson index and Pielou’s evenness index of skin flora Alpha diversity,but also increased the skin flora diversity through Beta diversity,and significantly increased the ratio of Firmicutes and Proteobacteria.In addition,dihydroquercetin can promote skin wound repair by reducing the abundance of Halomonas and Lactobacillus,thus the preliminary evaluation suggests that CPD has a promising application for drug healing systems.