| Objective: The sulfonated polyether ether ketone(PEEK)matrix composite was prepared,and the osteointegration properties of the sulfonated PEEK matrix composite were explored by repairing the femoral condylar bone defect of New Zealand white rabbits,so as to provide theoretical and experimental basis for the clinical application of PEEK bioactive composite and provide reference for the further study of bone graft materials.Methods:Sulfonated polyether-ether-ketone(SPEEK)was prepared after corrosion and sulfonation by concentrated sulfuric acid.Then,Graphene Oxide(GO)and Adiponectin(APN)were blended with SPEEK with the help of dopamine.The graphene oxide/sulfonated polyether ether ketone(GO-SPEEK),adiponectin/sulfonated polyether ether ketone(APN-SPEEK)and adiponectin/GO/sulfonated polyether ether ketone(APN-GO-SPEEK)composites were prepared.The physicochemical properties and cytology of the prepared SPEEK and its composites were studied in vitro.Then 24 healthy2-month-old New Zealand white rabbits with A body weight of 2.0-2.5kg were selected from the Animal Experimental Center of Southwest Medical University and randomly divided into four groups: A,B,C and D(n=6).Orthopedic electric drill was used to drill the bone defects of bilateral lateral femoral condyle of experimental rabbits in each group,and the standard model of bone defects of rabbit femoral condyle was established.Then,the prepared SPEEK,GO-SPEEK,APN-SPEEK and APN-GO-SPEEK materials were implanted into the condylar bone defects of rabbits in group A,B,C and D,respectively.Fluorescent labeling was performed by intraperitoneal injection of calcein 30mg/kg two weeks after surgery.Four and eight weeks after the operation,three rabbits in each group were sacrificed by air embolization,and the complete femur specimens were taken to observe the callus growth around and on the surface of the implant material,and whether the implant material loosened,moved or infected.Soft tissue was removed from the femur samples taken 4 weeks and 8 weeks after surgery.X-ray film,micro-CT detection,hard histological observation with methylene blue and acid fuchsin staining and confocal observation,pull-out experiment and scanning electron microscope observation were performed to analyze the formation of new bone at the interface.SPSS 25.0 software was used for statistical analysis of the experimental data.Results:(1)In vitro studies show that the constructed composites have the following characteristics:(1)After sulfonation,PEEK material forms a uniform nanometer three-dimensional porous structure on the surface;(2)GO and APN can form a uniform coating on the surface of SPEEK,and increase the surface roughness.(3)After GO and APN modification,the static water contact Angle on the surface of SPEKK material decreased obviously,and the hydrophilicity increased.(4)GO and APN modified SPEEK showed good cytocompatibility and could induce and promote osteogenic differentiation.(2)The modeling of 24 New Zealand white rabbits was successful,the operation time was about 20-30 min,there was no femoral nerve injury during the operation,and the amount of blood loss was small,about5-10 ml.Two weeks later,the gait of the experimental rabbits basically returned to normal,and the surgical incisions were all healed in one stage without dehiscence,obvious redness,swelling,oozing blood and exudation.All the experimental animals had no special mental and behavioral abnormalities after the operation,and all survived to the sampling stage.Samples were collected at4 and 8 weeks after operation:(1)Gross observation and X-ray examination showed callus formation around and on the surface of materials in each group,but the size and number of callus formation were different in each group.At the same time point,the formation of bone callus in group D was more and the quality was better than that in group A,B and C.(2)Micro-CT test: 4 weeks after surgery,a small number of new bone trabeculae were formed around the implant materials in each group.At 8 weeks after the operation,new bone was formed on the surface of the implant material: the bone trabecula formed in group A was few and sparse;The bone trabeculae formed in group B and C were more and more closely arranged.The bone trabeculae formed in group D were closely arranged and fused with each other.The Number of bone trabeculae,trabeculae thickness,bone Trabecular space and bone Volume/Total Volume(BV/TV)were better in the same group eight weeks after surgery than four weeks after surgery.The t-test of two independent samples within the group showed statistically significant difference(P < 0.05).Tb.N,Tb.Th,Tb.Sp and BV/TV of group D were better than those of group A,B and C at the same time point 4 weeks and 8 weeks after surgery.One-way analysis of variance showed statistically significant difference between groups(P < 0.05).(3)Hard histological sections were stained with methylene blue and acid fuchsin: 4weeks after operation,new bone tissue was occasionally observed on the surface of the materials in each group.The material-bone interface of group A was mainly A large number of soft tissues,while the material-bone interface of group B,C and D was connective tissue fibrous membrane.At 8 weeks after operation,A little new bone tissue was found on the surface of the material in group A.There are many new bone tissues on the surface of B and C materials,which grow into the pore structure.A large amount of new bone tissue grows on the surface of group D and grows into the pore structure of the material.(4)Laser confocal microscope observation: new bone formation with fluorescent labeling was observed in hard tissue sections of each group 4 and 8 weeks after operation.The new bone formation in group D was better than that in group A,B and C at the same time point.(5)The results of the pushout experiment: the maximum pushout load of each group of materials at 8 weeks after surgery was significantly higher than that at 4 weeks after surgery.The t-test of two independent samples within the group showed statistically significant difference(P < 0.05).The maximum load value of group D was higher than that of group A,B and C at the same time point 4 weeks and 8 weeks after surgery.One-way analysis of variance showed statistically significant difference between groups(P < 0.05).(6)Scanning electron microscope(SEM)observed that pore structures of different sizes were uniformly formed on the surface of each material.Four weeks after operation,new bone growth could be seen occasionally on the surface and pores of group A,while A small amount of new bone growth could be seen on the surface and pores of group B,group C and group D.A lot of new bone growth was observed on the surface and pores of group A,B and C 8 weeks after operation,while the surface and pores of the materials in group D were covered by abundant new bone.Conclusion: SPEEK,GO-SPEEK,APN-SPEEK and APN-GO-SPEEK all showed good biocompatibility and osteogenic activity.APN-GO-SPEEK composite material can effectively repair rabbit femoral condyle bone defect,and its in vivo osteointegration performance is better than that of SPEEK,GO-SPEEK and APN-SPEEK,which has great application value in bone defect repair materials. |
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