Study On Treatment Of Bone Defect Repairing With Antibiotic Loaded SF/CS/nHA Bone Scaffold Supplemented With BMSCs

Objective 1.To investigate the preparation,physiochemical properties and sustained-release ability of antibiotic-loaded bone tissue scaffolds.2.To investigate the anti-infection ability and osteogenesis of antibiotic-loaded scaffolds.3.To investigate the effect of antibiotic-loaded scaffolds combined with cells on the repair of bone defects and the mechanism.Methods 1.Antibiotic-loaded scaffolds were prepared by freeze-drying and chemical crosslinking techniques.Gross observation and SEM observation were carried out.The scaffolds were tested for mechanics,porosity,expansion rate,dissolve-loss ratio and elemental composition.The drug sustained-release curve was plotted by determining the release concentration.2.A total of 36 New Zealand rabbits were randomly assigned to establish an animal model.Rabbits in the experimental group were implanted with antibiotic-loaded scaffolds;rabbits in the control group were implanted with common scaffolds,and the blank group was put aside.Gross observation,X-ray,pathological examination and histological grading were performed from the 1st month to the 4th month after the operation.3.BMSCs were cultured.The experimental group was an animal model implanted with antibiotic-loaded scaffolds injected with BMSCs.The control group was an animal model implanted with antibiotic-loaded scaffolds that contained no cells.The blank group was an animal model with bone defects.HE,toluidine blue,masson staining and SEM observation were performed on the specimens obtained after the operation.The number of osteoblasts and the osteogenic area at each time point and of each staining resultResults 1.Scaffolds with sustained-release levofloxacin were constructed.In terms of the match to the requirements of the bone tissue engineering,the best performance among these scaffolds was as follows:anti-pressure ability 5.78MPa,tensile resistance 1.87MPa,porosity 91.25%±2.35,water absorption 135.65±4.56%,and dissolve-loss ratio 22.84±1.06%.2.Through SEM scanning,the average pore size of the ideal scaffold was seen as 86.67um.The energy spectrum analysis and mapping results showed that the average weight of calcium ions in the scaffold was 21.13%,and the distribution was even.3.The drug release curve showed a burst effect at dl-d3 and stable release at d4?d15.4.At the 1st month after the operation,the experimental group was free from infection and suppuration in the wounds,while inflammation or death occurred in both the control group and the blank group.5.The results of HE staining after the operation showed that in the experimental group,crowds of osteoblasts were arranged in the matrix and the cell morphology was good.6.The Lane-sandhu histological scores of the experimental group at each time point was higher than the control group and the blank group(P<0.05).7.Both scaffolds combined with cells and uncombined with cells were eventually degraded.Typical osteoblasts could be observed in various pathological stains.8.At the histological level,the scaffolds in the experimental group had more osteoblasts and a greater osteogenic area than the control and blank groups(P<0.05),9.Trabecular bone,Haversian canals,osteoblasts and other typical structures were observed in the 3 stains.Through SEM,the cells and their three-dimensional structures were observed.Conclusion 1.Antibiotic-loaded scaffolds had antibiotic sustained-release effects and good physicochemical properties,meeting the requirements of tissue engineering scaffolds and providing new options for the treatment of bone defects and bone infections.2.Antibiotic-loaded scaffolds showed good anti-infection ability and osteoinductive effects in the repair of bone defects.3.Both scaffolds combined with cells and uncombined with cells were eventually degraded.Typical osteoblasts were observed in various stains,suggesting that both kinds of scaffolds had good biocompatibility and osteoinductivity.4.At the histological level,scaffolds combined with cells had a better repair effect.5.At the histological level,all the four methods could be used to observe typical structures.SEM had more advantages in bone cell morphology analysis.Masson staining had advantages in qualitative analysis.