| Background:Spinal tuberculosis is the most common extrapulmonary tuberculosis,which often leads to bone destruction,and local infection is difficult to control,slow healing,high disability rate,seriously affecting the quality of life of patients.Objective: To construct a new type of isoniazid-loaded biomimetic mineralized bone collagen implants,so that the drug in the local long-term slow release,and promote bone formation.We constructed the scaffolds and evaluated the drug sustained release,degradation and osteogenic properties of the scaffolds in vivo.Methods: A novel isoniazid-loaded collagen scaffold was constructed with Nano hydroxylapatite(n HA)and type I collagen as raw hydroxylapatite to simulate the biomimetic mineralization of bone tissue.The stent was dissolved in PBS,and the absorbance was determined by UV photometer to calculate the amount of drug,thus calculating the drug loading and encapsulation rate of the stent.The inorganic components in the isoniazid-loaded scaffolds were determined by X-ray diffraction(XRD),and the microstructure of the scaffolds was observed by field emission scanning electron microscopy(SEM)The bone collagen scaffolds were implanted subcutaneously in mice,3 mice were killed every week after operation,and the degradation degree of the scaffolds and the sustained-release amount of drugs were detected,the mice in the experimental group were repaired with the scaffold,while the mice in the control group were not implanted with the scaffold.After a period of time,the samples were detected by Micro-CT,HE staining and immunohistochemistry to analyze the Biocompatibility and osteogenesis of the scaffold.Results: The isoniazid-loaded collagen scaffolds were prepared by biomimetic mineralization and self-assembly,and the drug loading and entrapment efficiency were(6.25 ±0.48)% and(65.54 ± 2.34)%,respectively,the characteristic diffraction peaks appeared on the Crystal Plane(002),(211),(112),(300),(222),(213),(004),which were consistent with the NHA standard card(JCPDS73-0432),the main inorganic component is NHA,and the porous structure of the scaffolds was observed by SEM.The drug release rate was(16.31 ±6.38)% in the first week and(72.56 ± 7.29)% in the 12 th week after the subcutaneous stent was removed.The scaffolds also showed good biodegradability in mice,with a degradation rate of(64.50 ± 6.05)% at the 12 th week.At the 12 th week after modeling,the tissues of heart,liver,lung and kidney were taken and made into paraffin section,then HE staining was performed to detect the histological changes,the stent is Biocompatibility.At 6 weeks and 12 weeks after operation,the skulls of rats were examined by Micro-CT,and the related parameters were analyzed,at the 12 th week,the new bone of the experimental group covered almost the whole defect with only a few pores,while the control group had some osteogenesis along the edge,there were significant differences in bone density,bone surface area,bone volume and bone volume fraction between experimental group and control group.The results of HE staining showed that there were more soft tissue and angiogenesis in the bone defect.Statistical analysis showed that the number of angiogenesis in the experimental group was higher than that in the control group.The expression of OCN and BMP-2 protein was significantly higher in the stent group than that in the control group.Optical density analysis with Image J software showed that the expression of OCN and Bmp-2 in bone defect in the scaffold group was significantly higher than that in the control group.Conclusion: We constructed isoniazid-loaded collagen scaffolds.Through in vivo experiments,it was found that the drug in the stent can be released slowly for a long time and has good degradability.Bone defects were repaired with stents,which were found to have good Biocompatibility and osteogenesis. |
PDF Full Text Request