Biocompatibility of freeze-dried antigen-extracted sheep cancellous bone scaffolds / 中国组织工程研究

ABSTRACT

BACKGROUND:Xenogeneic bone has a natural porous structure that is similar to human bone. In the treatment of bone defects, the porous structure is helpful to guide bone regeneration, but different degrees of immune responses wil be caused during the implantation process. OBJECTIVE:To prepare a freeze-dried antigen-extracted sheep cancelous bone scaffold and to evaluate its biocompatibility. METHODS: The sheep vertebral cancelous bone was colected to prepare two kinds of antigen-extracted heterologous bone scaffolds that were treated with chemical methods as chemical group and treated with chemical methods+cryopreservation at a-80℃ refrigerator for 4 weeks+drying in vacuum apparatus+60 RESULTS AND CONCLUSION:Freeze-dried bone had no cytotoxicity, no acute toxicity and heat reaction, and was negative for the intracutaneous stimulation test. The scaffold in the chemical group had cytotoxicity and mild irradiation as freeze-dried bone group. (1)Cytotoxicity test Bone marrow mesenchymal stem cels isolated from sheep were cultured in extracts of the chemical group, free-dried bone group and Dulbecco’s modified Eagle’s medium/Ham’s nutrient mixture F-12. (2) Heat reaction and acute toxicity tests Extracts from the chemical group, freeze-dried bone group and normal saline were respectively injected into the ear vein of rabbits. (3) Intracutaneous stimulation test Extracts from the chemical group, freeze-dried bone group and normal saline were respectively injected subcutaneously into the back of rabbits. Co acute toxicity reaction, sent heat source and had mild irritation. Results show that after freeze drying processing, the sheep vertebral cancelous bone has good biocompatibility, can meet the requirements of bone tissue engineering, but the bone that through chemical processing exhibits a relatively poor biocompatibility that cannot achieve the safety standard of biological scaffold materials.