| Objective To investigate the experimental method of animal models of chronic refractory osteomyelitis Preparation and characterization.Methods1.Pellets made from nano-hydroxyapatite/chitosan/konjac glucomannan scaffolds loaded with cationic liposomal vancomycin were implanted in the medial side of the thigh of New Zealand white rabbits or dipped into phosphate buffer. Tissue blocks surrounding the biomaterials and the nano-hydroxyapatite/chitosan/konjac glucomannan scaffolds loaded with cationic liposomal vancomycin pellets were took out after2,4,6,8,10,12,14and16weeks, respectively. Histological study was taken to investigate the tissue reaction of the material and evaluate its biocompatibility. Scanning electron microscopy(SEM)and measurement of gravity were used to make out the biodegradation characteristics of nano-hydroxyapatite/chitosan/konjac glucomannan scaffolds loaded with cationic liposomal vancomycin both in vivo and in vitro.2. Based on previous literature prepared rabbit model of chronic osteomyelitis, determined to give the model a thorough debridement and sensitive antibiotic treatment for2weeks, and then observe the clinical manifestations, general view, X-ray and the line of bone marrow tissue bacterial culture, organizational observations, and finally to determine chronic refractory osteomyelitis model on the basis of histological.3. Fifty-one New Zealand white rabbits, weighing1.5-3.0kg (mean weight±standard deviation,2.22±0.44kg),6months, were selected to produce chronic infection of the tibia bone defect model for this study. Pathogens were Staphylococcus aureus. After the success of preparation rabbit bone defects in chronic infection,48survival models were randomly divided into4groups, group A:no treatment after debridement; B group:nano-hydroxyapatite/chitosan/konjac glucomannan composite scaffold group; C group:vancomycin nano-hydroxyapatite/chitosan/konjac glucomannan composite scaffold group; group D:vancomycin liposome nano-hydroxyapatite/chitosan/KGM composite scaffold group. After debridement, corresponding scaffold of each group were implanted in bilateral bone defect, respectively. After8weeks of treatment, the bacterial culture,X-ray,HE staining, general observation and the measurement of the longest diameter of bone defect were done.Results l.The nano-hydroxyapatite/chitosan/konjac glucomannan scaffolds loaded with cationic liposomal vancomycin test pieces degraded into small particles.The biodegradation tendency in vivo was similar to that in vitro. There was no abscess formation and tissue necrosis surrounding the implanted materials. Little inflammatory reaction due to materials implanted were observed.2. In all33animals,10animals had soft tissue mass,20animals x-ray film prompted local soft tissue swelling, bone hyperplasia, low-density hollow shadow;25bone marrow bacterial culture were positive,21histological observation showed chronic inflammatory.3.4weeks after modeling, for all48animals diagnosed with osteomyelitis,all or some signs of bone infection, including periosteal new bone ormation, destruction of bone, and soft tissue swelling, were observed radiographically. Norden score was greater than3points, the average score (3.83±0.52) points.8weeks after treatment the general observation:C, D group sinus had healed, A, B group sinus remnants; gross bone pathologieal score C, group D was significantly better than the A, B group (P<0.05). Bone defects observed:D Group bone defects had been repaired completely, the measurement results of the longest diameter of bone defects significantly better than the other three groups (P<0.05). X-ray observation:C, D group showed new bone formation, groupA, B periosteal reaction and marrow low-density shadow were observed; Norden score D group exceeded the other three groups (P<0.05). Histological observation:HE staining C, Dgroup a large number of trabecular bone formation, fibrosis, and no obvious signs of infection, A,B group still neutrophil accumulation; Smeltzer score C, D group were significantly better than group A,B (P<0.05). Bacteriology:D group negative rate was significantly higher than the other three groups (P<0.05).Conclusion1.The biodegradable material nano-hydroxyapatite/chitosan/konjac glucomannan scaffolds loaded with cationic liposomal vancomycin has good histocompatibility and appropriate biodegradation characteristics, applicable to animal experiment in vivo. The biodegradable material n-HA/CS/KGM scaffolds loaded with cationic liposomal vancomycin is worth to be researched and studied further.2.21experimental animals were prepared successfully for model of chronic refractory osteomyelitis.Operation this method can be successfully prepared animal models of chronic refractory osteomyelitis, with a success rate of63.6%.3. Vancomycin liposome nano-hydroxyapatite/chitosan/konjac glucomannan composite scaffold can be a good treatment of chronic refractory infectious bone defects in rabbits, providing a new strategy for the therapy of bone defects in chronic infection. |
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