Preparation Of Magnesium-containing Aecellularized Bovine Bone Matrix Scaffold And Experimental Study In Vivo And In Vitro

Objective:To explore the physicochemical properties of magnesium-containing acellular bovine bone matrix scaffold（ABBM-Mg）prepared by ion exchange method and its effect on the proliferation and differentiation of MC3T3-E1 cells in vitro,and to verify that the scaffold promotes rat mandibularity through animal experiments repair of bone defects.Methods:Aecellularized bovine bone scaffolds were prepared by physical and chemical methods,and magnesium and aecellularized bovine bone scaffolds were compounded by ion exchange method.Scanning electron microscope and energy spectrum analysis were used to observe the microstructure and element composition of ABBM and ABBM-Mg scaffolds.X-ray diffraction analysis and Fourier infrared spectroscopy were used to analyze the chemical structure of ABBM and ABBM-Mg scaffolds.Inductively coupled plasma was used to detect the Mg²⁺content and release rate in the ABBM-Mg-containing stent.The mechanical properties of ABBM and ABBM-Mg scaffolds were tested with a biomechanical testing machine.The biocompatibility of ABBM and ABBM-Mg scaffolds was detected by CCK-8 and live dead cell staining.Alkaline phosphatase staining,alizarin red staining,immunofluorescence and RT-q PCR were used to detect the osteogenic differentiation and related gene expression of ABBM and ABBM-Mg scaffolds.The rat mandibular defect model was used,and the bone repair ability of ABBM and ABBM-Mg scaffolds in animals was evaluated by Micro-CT,histological HE staining and Masson staining.Results:The results of scanning electron microscopy and energy spectrum analysis showed that mineralization containing magnesium was re-deposited on the surface of the three-dimensional porous ABBM;XRD,FTIR and ICP detection results showed that Mg²⁺can be successfully combined with ABBM by ion replacement,and the mixed The content was 11.67mg/g;there was no significant difference in the compressive strength of the composite Mg²⁺before and after the stent material（P>0.05）.In addition,the in vitro release of Mg²⁺in the composite scaffold material can reach 8%within 4 weeks.CCK-8 and scanning electron microscopy show that ABBM-Mg scaffold can promote the proliferation of MC3T3-E1 cells.Compared with the ABBM scaffold,the ABBM-Mg scaffold promotes the osteogenic differentiation of MC3T3-E1 and up-regulates the mRNA expression of Runx2,OPN,ALP and Col-Ⅰ.The results of Micro-CT and histological HE/Masson staining of the rat mandibular animal model show that compared with the ABBM scaffold,the ABBM-Mg scaffold has better bone repair ability in vivo.Conclusion:The ABBM-Mg scaffold material prepared by ion exchange method has good biocompatibility,promotes the osteogenic differentiation of MC3T3-E1,and can effectively repair rat mandibular defects.