Hyaluronic Acid Hydrogel For Healing Of Diabetic Skin Injury And Its Biological Response

Diabetes is a universal disease in the world.The cell phenotype in the damaged skin of diabetic patients is abnormal,such as fibroblasts cannot migrate effectively,and the remodeling of the extracellular matrix is unbalanced,which would lead to the ineffective healing of the skin damage for diabetic patients and can even further develop to the chronic skin anabrosis.Hydrogels have been widely used as modern wound dressings.However,because of the difficulty of healing the skin wounds of diabetic patients,new requirements are required urgently.How to improve the biological functions of the hydrogel has more clinical application value,such as regulating the skin repairing and regeneration of diabetic patients.Metformin is commonly used as a hypoglycemic agent in clinical practice.Meanwhile,it has many abilities,including anti-inflammatory and hypoglycemic effects.To explore the role of metformin in diabetic skin repair,in this article,we prepared gelatin microspheres by a single aggregation method and loaded them with metformin The gelatin microspheres are then incorporated into the hyaluronic acid-collagen interpenetrating network hydrogel,in which hyaluronic acid and collagen are the main components of the extracellular matrix.Subsequently,in vitro cell experiments and in vivo animal experiments,both at high-glucose mode,were carried out to verify the ability for promoting skin regeneration.The main research contents and conclusions are as follows:1.Preparation and characterization of interpenetrating network hydrogels incorporating metformin-loaded gelatin microspheresBy aldehyde modification and hydrazide modification of hyaluronic acid,a dynamic hydrazone cross-linked hyaluronic acid hydrogel with self-healing properties is obtained.The collagen network is further introduced.Compared with the single network,the stability of the hydrogel system with the interpenetrating network is improved.The gelatin microspheres encapsulating metformin were prepared by a single coacervation method.The drug loading rate was 2.552%,and the encapsulation rate was 24.655%,respectively.The drug-loaded gelatin microspheres were successfully incorporated into the hydrogel system,which can retard the early-stage release rate.Meanwhile,the degradation of gelatin drug-loaded microspheres can also provide more growth space for cells.2.In vivo experimental study of composite hydrogelTo investigate the effects of the prepared hydrogel on the adhesion,proliferation,and migration for fibroblasts and macrophages in a high-glucose environment,in this study,mouse NIH-3T3 fibroblasts and mouse RAW 264.7 macrophages were adopted.The results showed that the prepared hydrogel can effectively promote the proliferation of fibroblasts and enhance their ability to infiltrate from the surface of the gel;the hydrogel with drug-loaded microspheres can also promote the transfer of macrophages to M2 Type transformation,and further promote the migration of fibroblasts.3.In vitro experimental study of composite hydrogelIn this study,to further investigated its ability to promote skin tissue regeneration in the diabetic mouse skin damage.we constructed a diabetic mouse skin defect model and covered the prepared hydrogel material on the wound surface by in-situ gelling.The results showed that the prepared material can effectively promote wound closure at 4,8,and 12 days after surgery;significantly promote angiogenesis and collagen fiber remodeling at 12 days after surgery.