Preparation,characterization And Effect Of Epigallocatechin Gallate Nanoparticles On Wound Healing In Diabetic Mice

Epigallocatechin gallate(EGCG)is the most abundant and active active ingredient in green tea.EGCG has a variety of physiological activities,such as anti-oxidation,anti-inflammatory,and prevention of obesity.However,EGCG is unstable in nature and easily oxidized or polymerized by the influence of the external environment.Usually,the stability of EGCG is improved by embedding EGCG with nanomaterials.Diabetes mellitus(DM)reduces the quality of life of patients,and there are many complications,delayed wound healing is one of them.About 50%-70%of amputations in diabetic patients are related to diabetic foot ulcers.Studies have shown that EGCG can accelerate wound healing in diabetic mice.This subject improves EGCG stability by embedding EGCG and vitamin C(Vitamin C,Vc)with gelatin(Gel)and chitosan(Cs),and explores its promoting effect on diabetic wound healing.The main research contents and conclusions of this topic are as follows:(1)Optimize the preparation conditions of the nanoparticles,and use the average particle size,Zate potential,polydispersity index(PDI),embedding rate,drug loading as evaluation criteria to obtain a concentration of 0.1%(w/v).When the pH is 5.4 and the ratio is Vc:EGCG:gelatin:chitosan=0.2:3:1:1,and prepared by magnetic stirring at 300r/min for 30min were optimal.(2)The characterization and embedding efficiency of the best EV nanoparticles(EGCG-Vc-Gel-Cs nanoparticles,EV NPS)were measured,and the embedding rate was measured to be as high as 68.39±2.60%,and the drug loading was 675.15±8.50mg/g.Transmission electron microscopy showed that it was uniformly spherical,without obvious aggregation,and the particle size was 200nm.Fourier transform infrared spectroscopy proves that the hydrogen bonds in the nanoparticles are strengthened,and there is aromatic ring tensile vibration,which proves that EGCG is embedded.Using 10%sucrose as a lyoprotectant can make nanoparticles better reconstituted.(3)Intraperitoneal injection of streptozotocin(STZ)at a dose of 120 mg/kg to induce male ICR mice as a diabetes model.Five days later,the success rate of the diabetes model reached more than 75%,and no mice died.Unmodeled mice need to be supplemented with STZ at a dose of 50mg/kg.(4)The mice were divided into five groups,one group was normal mice(saline),and the remaining four groups were diabetic mice.After the mice were depilated,a hole with a diameter of 6 mm was removed from the back of the mice to remove the full-thickness skin wound.They were administered with saline,No-load NPS solution,10%EGCG aqueous solution,and 10%EV NPS solution.Dosing once a day,subject to covering the wound,taking ten days as the experimental cycle.(5)Take photos on the day of the experiment and every other day after the experiment to observe the progress of wound healing and calculation of wound healing rate.The results showed that the healing area of the mice in the EV NPS group reached 47.33±2.55%on the second day,which was significantly higher than that of the other groups.On the sixth day,the scabs of mice in the EV NPS group had fallen off.On the eighth day,the skin of the wound in the EV NPS group was smooth and no scars were seen.(6)Three mice were dissected on the fifth and tenth days respectively,and the skin of the wound was cut vertically for staining,including hematoxylin-eosin staining,Masson staining(for observation of collagen production and quantity)and immunohistochemistry Staining(observing the infiltration of inflammatory cells).Tissue staining results showed that,the EV NPS group can significantly accelerate the wound healing speed of diabetic mice compared with the model group and the EGCG group.The possible mechanism was that EV NPS could make collagen production faster and reduce inflammatory cell infiltration.In summary,EV NPS could promote the healing of diabetic wounds and provide new ideas for the development of new drugs for the treatment of diabetic wounds.