Experimental Study On Attapulgite/CollagenⅠ/Polyvinyl Alcohol Composite Scaffold Repaired Bone Defect

Our previous experiments showed that the addition of attapulgite in collagen can effectively promote the differentiation of bone marrow mesenchymal stem cells into osteogenic bone and promote bone tissue regeneration,but the optimal proportion of attapulgite is not yet clear.This study was to study the application of different proportions of attapulgite（ATP）/collagenⅠ（ColⅠ）/polyvinyl alcohol（PVA）composite scaffold materials in the repair of bone defects.Through material characterization,physicochemical properties,biocompatibility,osteoinduction,bone defect repair effects and other experiments to evaluate the material’s ability to repair.The details are as follows:1.The preparation of attapulgite/type Ⅰ collagen/polyvinyl Alcohol composite scaffold and the study of characterization and osteoinductivity:Different proportions（0-70%,divided into group 0、1、2、3、4、5、6、7）ATP of scaffold materials were prepared though freeze-drying.The group 2-4 ATP scaffold materials exhibit better water absorption expantion rate and compressive strength.The result of cck-8suggested group 3-4 were the best proportion of attapulgite,which showed the significant proliferation compared with others.The statistics of Real-time PCR showed the expression of Runx-2mRNA of group 3-6 were higer than others after co-cultured with cells for 14 days,at 21st day the expression decrease in every group,the expression of OPN mRNA of group 1-4 were significantly up-regulated compared with group 0,at 21^st day the expression decrease in every group,the expression of OC mRNA OF group 1-4showed significantly increasing compared with group 0 at 14th and 21st day,the expression of Osterix mRNA of group 1-6 were up-regulated significantly at 21st day,the expression of ALP mRNA of group 3-4 show significantly up-regulated compared with others at 14th day.2.Evaluation of the ability of ATP/ColⅠ/PVA composite scaffolds for repairing rabbit bone defect:According to the experimental results of scaffold materials and characterization and in vitro osteoinductivity,（0%,20%,30%,40%）ratio of ATP/ColⅠ/PVA composite scaffold materials and HA/ColⅠcomposite scaffold materials were selected as the experimental group.The results of animal model experiments showed that the composite stent materials in all proportions had good biocompatibility,no abscesses and inflammatory reactions were found.Micro CT results showed that 30%of the ATP/Col 1/PVA composite scaffold material had higher amounts of new bone than other groupsIn conclusion,Among all the proportions of composite scaffolds,the 30%ATP group showed outstanding performance,not only rich three-dimensional pores,strong mechanical properties and biocompatibility,but also good physicochemical properties and osteoinductive repair ability.In the future,it is expected to become a bone tissue replacement material that can be put into practical use,providing new ideas and data for the future research on composite bioscaffolds containing ATP.