In Vitro And In Vivo Study Of 3D Printed Wapiti Antler Powder Tissue Engineering Bone Scaffolds

Objective: To construct a new scaffold material(wapiti antler powder/PVA scaffold),and evaluate its feasibility as a bone tissue engineering scaffold by testing its physical and chemical properties,biological properties,acute toxicity test and ectopic osteogenesis model.Methods: The wapiti antler powder/PVA scaffolds were respectively prepared by 3D printing technology to test the porosity,pore size,water absorption,compressive mechanical properties and cytotoxicity test,acute toxicity detection,gross observation after replantation of rat renal capsule,HE staining and RT-PCR.Result:(1)Porosity and pore size: Comparison of wapiti antler powder/PVA scaffold with nano-hydroxyapatite/PVA(n-HA/PVA)scaffold,there was no difference in the porosity of the two groups,and the wapiti antler powder/PVA pore size were larger than that of the n-HA/PVA scaffolds(P=0.004).(2)Water absorption: At different time points,the water absorption of the n-HA/PVA scaffolds were greater than that of the wapiti antler powder/PVA scaffolds,but The wapiti antler powder/PVA scaffolds had a longer duration of water absorption.(3)Compressive mechanical properties: the compression resistance of the two groups had no difference(P=0.243),but the toughness were better than that of the n-HA/PVA scaffolds.(4)Cytotoxicity test: the cell compatibility of the wapiti antler powder /PVA scaffolds were better than n-HA/PVA scaffolds.(5)Acute systemic toxicity test: After intraperitoneal injection of material extract,the rats in each group survived well during the observation period of 72 h,and there was no difference in body weight between the groups(P>0.05).(6)Related detection after replantation: When planting animals,the materials are divided into 3 groups: experimental group 1-BMSCs cell membrane composite wapiti antler powder / PVA scaffold;experimental group 2-simple wapiti antler powder / PVA scaffold;Control group-empty scaffold group.HE staining showed that at 1 month,cell membrane-scaffold group and simple scaffold group were surrounded by connective tissue and blood vessels,and there were more inflammatory cell distributions.There was no significant difference between the two experimental groups.At 2 months,the inflammatory cells in the two experimental groups decreased.In the cell membrane-scaffold group,light blue cartilage-like substances appeared around the connective tissue,and the control group had a large amount of adipose tissue and a small amount of connective tissue and blood vessels in both time periods.RT-PCR analysis showed that the expression of RUNX2 was prolonged with time.The upward trend,while the expression of COL-1,IL-1 and RANKL showed a downward trend,and the gene expression of each group was different from that of the control group(P<0.01).Conclusions: The wapiti antler powder/PVA scaffold has good mechanical properties,and it has good biocompatibility in both cell and in vivo experiments.In the in vivo simulated environment,BMSCs cell membrane composite wapiti antler powder/PVA scaffolds group showed better osteogenesis.Advantages can be used as a new direction in the study of xenogenic bone scaffold materials.