The construction of double gene-modified dog bone marrow mesenchymal stem cells tissue engineered bone with Zirconia-Hydroxyapatite biological materials and its osteogenesis ability in vitro

Abstract

Objective To establish a new tissue engineering bone with Zirconia-Hydroxyapatite (HA/ZrO2) composite bioceramic as scaffold, combined with dog bone marrow mesenchymal stem cells (BMSCs) coexpressed with vascular endothelial growth factor 165(VEGF165) and bone morphogenetic protein-2(BMP-2) by lentiviral transfection and observe its osteogenesis ability in vitro. Methods The HA/ZrO2 graded composite was synthesized by dry-laying sintering method with polymer foam template. Then made the honeycomb HA/ZrO2 graded composite as scaffold with VEGF165/BMP-2 double gene-modified BMSCs construction a new tissue engineering bone. BMSCs of each group were collected and seeded on the HA/ZrO2 graded composite, the scaffolds combining BMSCs were scanning electron microscopy observation after cell seeding, and Alkaline phosphatase activity (ALP) staining as well as ALP activity and immunohistochemistry assay were performed after cell seeding. Results The surface of the new tissue engineering bone was porous structure and the pore size was from 125-550 μm.The average compressive strength was 812.25 MPa and the maximum strength was 987.12 MPa. After seeding BMSCs onto the scaffolds, SEM observation showed that MSCs grew and proliferated well. The ALP activity observed in the co-transfection group was higher than that of groups(F=1 029.398, P<0.01), collagenaseⅠand osteocalcin which were osteoblast secrete proteins could be observed in co-transfection group by immunohistochemistry assay. Conclusions The honeycomb HA/ZrO2 graded composite was a good scaffold which was suitable for seed cells proliferation, and the combined use of VEGF165 and BMP-2 gene can produce better osteogenesis for BMSCs in vitro than each single gene alone. Key words: Tissue engineering; Bone; Mesenchymal stem cells; Bone marrow; Genes, modifier; Bone morphogenetic protein 2; Vascular endothelial growth factors