| Objectives To observe the healing process of nano-hydroxyapatite/chitosan/resol resin(CHA-RS)composite for repairing mandibular defect in SD male rats,observe the osteogenic properties and effects of this new material,and provide experimental basis for clinical application,and preliminarily determine the application prospects of this new materia.Methods 1 Experimental materials: in this experiment,nano hydroxyapatite/chitosan/phenolic resin was mixed into composite materials by coprecipitation method.The physical and chemical properties and biological properties of the experimental materials were preliminarily determined.The materials were observed by scanning electron microscopy,the porosity was calculated,and the in vitro degradation rate was determined.2 Animal experiment: 45 experimental male SD rats were randomly divided into three groups and made into A mandibular defect model.CHA-RS composite material was used to implant the defect in group A,nHAP in group B,and no implant material was used in group C.Grouping 4/6/8 weeks postoperatively in batches random kill rats,each group of five at a time,after separation of mandibular defect healing of first from general observation,then histology slice observation,using IPP6.0 software to calculate new bone area percentage of the total area of the recipient area,and the expression of collagen type ? positive value average optical density(MOD)of the analysis,the results for statistical analysis.Results 1 CHA-RS composites were prepared,and the surface of the material was observed by scanning electron microscopy to be uneven,ranging from tens to hundreds of nanometers in size.The material was loose and granular,with pores,and the pores were connected with each other.The porosity is about 90%,similar to natural bone tissue,and the degradation rate is good.2 HE staining slices,Masson trichromatic dyeing,collagen type ? immunohistochemical staining results,4 weeks,the experimental group microscopically the newborn small patches of trabecular bone,a large number of osteoblast and fibrous tissue exist,the control group have more new bone matrix,new bone trabecular relatively less experimental group and blank group is a large number of inflammatory cells infiltration,on the edge of the defect in the area there is a small amount of osteoblast and substrate fiber.At 6 weeks,trabecular bone connections were observed in the experimental group under the microscope,while the number of flaky bone trabeculae in the control group increased and showed a trend of gradual connection.Bone tissue defect areas were still observed in the blank group,but the range was narrowed.At 8 weeks,the bone defect site of the experimental group was almost filled with new bone trabeculae,and the new and old bone edges were not obvious.The bone trabeculae in the control group gradually spread and connected into a network,while the bone trabeculae in the blank group became thicker,but there were still osteoid fibers and osteoblasts arrayed around.The percentage of new bone area Sbone to the Stotal of the implanted area results: the ratio of new bone area increased in each group over time.In the comparison between groups,the new bone area ratio of the experimental group was greater than that of the control group and the blank group in the same period of time,and the difference was statistically significant(P < 0.05).Results: the collagen type ? positive expression rate of MOD values compared between group,as the growth of the time,? positive expression rate of collagen type.Comparison between different groups,collagen type ? positive expressionrate of the same period of time,the experimental group were better than the control group and the blank group,the difference was statistically significant(P < 0.05).The above results showed that the materials in the experimental group were significantly better than the control group and blank group in repairing the bone defect.Conclusions As a new type of scaffold material,CHA-RS polymer prepared by coprecipitation method is simple to make,easy to disinfection and shape,and has the function of promoting osteogenesis.It can be applied to the repair of bone defects.As a scaffold material for bone defect repair and tissue engineering,it has a good application prospect.Figure 41,Table 7,Reference 110... |
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