Pulp-capping With Vascular Endothelial Growth Factor (VEGF) In Rat Malors And The Preparation Of Microspheres Containing VEGF165 Gene

The ultimate goal of vital pulp therapy is to maintain vitality and function of the dentine-pulp complex,and the present paper focuses on the application of growth factor to the experimental pulp capping in order to preserve the vitality of dental pulp.Vascular endothelial growth factor is known to promote angiogenesis and vasculogenesis,which is closely related to the repair of dental pulp regeneration after injury.This paper was divided into two parts,the first part was designed to investigate the role of vascular endothelial growth factor in rat dental pulp after the effect of injury.The second part of the paper was in order to explore the production of a microsphere containing the VEGF165 gene. The prepared microsphere should have a certain degree of slow-release function, so that it could be applied to live animals in vivo.Part 1 Experimental Study of VEGF165 and BMP-2 in rat molar pulp cappingObjective:To investigate the role of VEGF165 or VEGF165 and BMP-2 in rat dental pulp after the effect of injury.Methods:Twelve adult male Wistar rats were used,each rat selected four first molars,and a total of forty-eight teeth was used in the experiment.Twelve rats were randomly divided into two groups,every group cotained six rats and twenty-four molars.Two groups were treated with a piece of collagen sponge with VEGF165 liquid or VEGF165 and BMP-2 mixed liquid respectively.In each group,two animals were randomly killed after one week,two weeks and six weeks and then the extracted teeth were processed for histological examination.The inflammatory response of dental pulp and reparative dentin formation under the hole were investigated.Results:VEGF165 group:A large number of inflammatory cells were gathered under the hole and there was significantly inflammatory response after one week.Bone-like dentin matrix was observed in some teeth after two weeks. Six weeks later,the dentin bridge was formed and the dental pulp tissue inflammatory response was disappeared.VEGF165 and BMP-2 mixed group:The dental pulp under the hole had marked inflammatory response after one week.There was scattered calcified material beneath the pulp hole after two weeks later.Six weeks later,the dentin bridge was formed,covering the surface of dental pulp hole.Conclusion:VEGF165 and BMP-2 can promote the wound healing of injured pulp,and they can be acted as a potential biological pulp-capping material.Part 2 Preparation of nanospheres containing VEGF165 gene and the study of its propertiesObjective:To prepare VEGF165-PLGA nanospheres and to investigate their generic characteristics,drug release characteristics in vitro.Methods:1.Get VEGF165 plasmid from the strains containing VEGF165 gene.2.The nanoparticles were prepared by high-speed mixing multiple emulsion solvent evaporation method,choosing biodegradable material PLGA as carrier material.3.Scanning electron microscopy was used to observe the surface morphology and structure of the nanospheres.The VEGF165 gene content and encapsulation efficiency were determined.In vitro conditions were simulated to study VEGF165-PLGA release characteristics.Results:The shape of VEGF165-PLGA nanoparticles is roundness,size is well-destributed,the mean diameter is between 300nm and 500nm.The encapsulation ratio reaches to 46.45%,the VEGF165 loading in the nanoparticles is 0.783%.The drug release reached 70%after two weeks. Conclusion:The prepared nanospheres have good properties including sustained release in vitro.