| Background:Burns are common injuries in both daily life and wartime while the incidence of burns is increasing in the modern war.Therefore,the study of burn treatment has important social and military significance.The key to the treatment of burns wounds is to anti-infection and promote healing.Traditional Chinese medicine has a long history and rich experience in the treatment of burns.Chinese medicine has shown good therapeutic effects in relieving wound pain,resisting infection,promoting wound healing,reducing scar formation,and enhancing immune regulation.However,decoction,ointment and powder are not suitable for use in modern clinical and battlefield environments.Therefore,it is of great significance to develop a novel burn wound healing material that combines Chinese medicine with modern preparation techniques and has both anti-infective and wound healing effects.Objective:To develop a novel burn wound healing material with a porous sponge-like structure that has both anti-infective and wound healing effects,we select baicalin,Bletilla striata gelatin,silver titanate with bacteriostatic effect and carboxymethyl chitosanhigh,which is a water-soluble polymeric film-forming material.Baicalin and Bletilla striata gelatin are the main active ingredients of traditional Chinese medicine Radix Scutellariae(Huangqin)and Rhizoma Bletillae(Baiji),which are commonly clinically used in the treatment of burns.The preliminary pharmacodynamics study of the material was conducted to lay the experimental basis for its clinical treatment of burns wounds.Methods:1.Sponge-like burn wound healing materials were prepared with different proportions of Bletilla striata gelatin and carboxymethyl chitosan,respectively,and the optimal ratio was confirmed by examining texture,elasticity,flexibility,and porous structure.Baicalin concentration and silver titanate species for antibacterial activity against Staphylococcus aureus and Escherichia coli were selected by bacteriostasis experiments.Freeze-drying method was used to prepare the novel porous material containing baicalin,Bletilla striata gelatin and silver titanate.The microstructure of the novel porous material was examined by scanning electron microscopy,and the physical properties such as porosity,water absorption,and air permeability were measured.Skin irritation test was conducted for safety evaluation.2.Antibacterial activity of the porous material was verified by disc diffusion test.The SD rat deep second-degree burn model was made by self-made soldering copper.The wounds were divided into baicalin-Bletilla striata gelatin-silver titanate composite porous material(BBSPM)group and baicalin-Bletilla striata gelatin composite porous material(BBPM)group,silver sulfadiazine(SSD)group and normal saline(NS)group by randomized self-control method.The wound healing rate,wound healing time,interleukin-1β,VEGF and other indicators were tested and paraffin sections were histological observed in order to study the burn wound healing effect of BBSPM.Results:1.The optimal ratio of Bletilla striata gelatin and carboxymethyl chitosan was 5% Bletilla striata gelatin: 4% carboxymethyl chitosan glue = 1:3.Baicalin has good antibacterial activity against Staphylococcus aureus,and the lowest effective antibacterial concentration is 20 mg/mL.The 100 mg/mL silver titanate suspension has good antibacterial activity against both Staphylococcus aureus and Escherichia coli.The novel BBSPM prepared by freeze-drying method has a spongy porous structure,dense pore distribution,and cross-linking with pores.The silver titanate particles are evenly distributed on the surface of the cover and in the pores.The average porosity is 90.43%,the average water absorption is 746%,and the average air permeability is 66.67%,which shows many excellent properties of porous materials.BBSPM has no skin irritation.2.Antibacterial experiments in vitro demonstrated that BBSPM has good antibacterial activity against Staphylococcus aureus and Escherichia coli.In vivo studies of SD rats with deep second degree burns found that after 3 days and 7 days of intervention,the wound healing rate of BBSPM group and BBPM group was significantly higher than that of the NS group and SSD group at the same time(P<0.05).Wound tissue histological observation showed that epidermal necrosis and exfoliation began to appear in the BBSPM group and BBPM group 3 days after intervention,prior to that did in NS group and SSD group.At the level of wound healing,the epidermis of BBSPM group and SSD group were completely repaired,and small blood vessel hyperplasia was observed,while wounds was unevenly repaired,the collagen fibers were highly proliferated and there are leeches in NS group.After 1 day and 3 days of intervention,the concentration of IL-1β in BBSPM group was significantly lower than that in the other three groups(P<0.05).After intervention for 3 days,the concentrations of VEGF in BBSPM group and BBPM group were significantly higher than that in the other groups(P<0.05),while the concentrations of VEGF in SSD group and BBPM group were significantly higher than that in the other groups after intervention for 7 days(P<0.05).The peak of VEGF concentration in the BBSPM group appeared 3 days after the intervention and the remaining three groups reached the peak 7 days after the intervention,while the fluctuation of VEGF concentration in NS group with time was not obvious.It has shown that in the early stage of burns,BBSPM can reduce inflammation,control infection and promote wound healing.Conclusions:BBSPM is a noval external preparation for burns that has effects of anti-infection and wound healing.It has a sponge-like porous structure,good hygroscopicity and breathability and shows good application value. |
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