| Background and ObjectiveOral is the channel of human body exposed to the environment,it performs the function of chewing,speech,breathing,sucking and swallowing and so on.The mucous mucosa in the mouth is mainly composed of chewing mucosa,mucosal mucosa and special mucosa,which is an effective barrier to prevent adverse irritation and trauma.If the epithelial mucosal integrity is destroyed,it will cause patients with swallowing,chewing,speech and other functions disorder.Moreover,the patient's physical and psychological health will be damaged.In recent years,owing to the accelerated pace of life,the heavy pressure is damaging people's physical,psychological and oral mucosa.Besides,oral mucosa trauma is also caused by car crash,fights,bad repair,chewing hard objects and unhealthy orthodontic attachment and so on.Gentle injures can cause mucosal ulcers,severe cases can cause local mucosal defects.It not only brings pain to the patient's body,but also causes functional disorder.The current repair of these mucosal ulcers and defects mainly contains anti-inflammatory analgesic and anti-infection-based,lacking of effective promotion of mucosal wound healing drugs.Therefore the pursuit of rapid and effective promotion of mucosal wound healing drugs becomes the focus of this research.Studies have shown that growth factors have the effect of promoting wound healing,but growth factors are expensive and nicotine prices are relatively inexpensive andreadily available.According to the recent reported literatures,low concentrations of nicotine can promote the formation of wound neovascularization,thereby accelerating the wound healing of diabetic rats.However,nicotine has fast metabolism in vivo,it's difficult to maintain efficacy in oral and sublingual.So this experiment plans to use nicotine slow-release method to maintain a constant low concentration.This subject to use polylactic acid-glycolic acid copolymer(PLGA)as a carrier material to make low concentration of nicotine sustained-release micro particles and make low-concentration nicotine / collagen membrane sustained-release micro particle system with collagen membrane as a scaffold,looking for a new idea for clinical treatment of nicotine.MethodsExperiment 1: Low concentration of nicotine sustained-release micro particles was synthesized by using polylactic acid-glycolic acid copolymer(PLGA)as carrier material,using milk-solvent evaporation method(w/o/w)with nicotine as raw material and measure the embedding rate,drug loading rate and release rate in vitro.Using collagen membrane as scaffold to make low concentration nicotine/collagen membrane sustained release micro particle system.Experiment 2: A total number of 48 Wistar rats(3-4-week-old)were randomly divided into two groups(24 animals per group)as follows :(1)Low concentration nicotine collagen membrane sustained release micro particle as the treated group.(2)Blank collagen membrane group as the control group.48 Wistar rats were made 3 mm diameter circular wound in the forepart palate,respectively.The rats of each group were divided into four subgroups: 0d,3d,7d and 10 d.Then 6 rats were sacrificed at 0d,3d,7d and 10 d,respectively.HE staining,general view and statistical analysis of the two groups on the palate mucosal wound healing process.ResultsExperiment 1: under electron microscope,the sustained release of nicotine sustained-release micro particles appeared to be three-dimensional spherical shape,uniform size,spherical surface roughness,and the average particle size was 3.0 ±0.2um.Three entrapment efficiency of nicotine sustained-release particles was measured,the drug loading rate were 50.2% and 4.12%.The drug release curve showed that there was the largest release of slow release particles at the 1 day,reduced from the second day and became stable from day the third day.The nicotine concentration fluctuated at 10-5-10-4mol / L in 3-10 days.The collagen fibers under the electron microscope showed three-dimensional loose porous type,intertwined into a three-dimensional network structure and the mesh was mostly irregular long spindle shape.Under electron microscopy,nicotine sustained release particles were fully across into and dispersed in the pores of the collagen membrane evenly,with particles embedded in it firmly.There was no significant difference between the two groups in the wound healing by statistical and digital image analysis at the third day according to the general observation and histology.The wound healing area of the nicotine collagen membrane sustained release micro particle group at the seventh day postoperatively(P <0.05).At the tenth day after operation,the wound was healed in the experimental group while the wound in the control group wasn't completely healed.Conclusion Low-concentration nicotine collagen membrane sustained-release micro particle system may play an important role of promoting the healing of rat palate mucosal wound... |
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