טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
Ph.D Thesis
Ph.D StudentSrouji Samer
SubjectUse of Bone Marrow Stem Cells, Growth Factors and Biological
Scaffold for Bone Repair
DepartmentDepartment of Medicine
Supervisor Ms. Erella Livne (Deceased)


Abstract

Healing of bone defects is often poor due to diminished availability of osteoprogenitor cells and growth factors. The potential application of biological scaffolds loaded with growth factors and bone marrow stem cells (MSCs) to enhance bone defect healing was examined. Bone defects were induced in rat femur, tibia or mandible. External fixation was performed prior to induction of segmental defects in order to stabilize the site. Hydrogel scaffolds containing either TGF-β1, IGF-1, TGF-β1 with IGF-1, hydrogel or saline were inserted into the defect. Calcified material was observed in defects after two-week treatment with TGF-β1. Bone defects treated with TGF-β1, IGF-1 or TGF-β1 with IGF-1 revealed significant bone formation after four and six weeks. X-ray images showed that bone was present after six weeks of treatment with TGF-β1 or TGF β1 + IGF1. Less pronounced bone induction was observed in control specimens and IGF-1. 3D CT images revealed that bone shape had been restored. Similar results were obtained in mandibular defects. Osteoprogenitor cells were selected from rat bone marrow cultured in DMEM medium supplemented ascorbic acid, β-glycerophosphate and dexamethasone. The selected subpopulation was identified by osteocalcin, BMP-RII, Alizarin red S, von Kossa and mineral deposition analysis by SEM and EDS. Positive osteocalcin immunostaining, Alizarin red S and von Kossa were observed after two weeks and BMP-RII after one week in culture. EDS analysis revealed deposition of calcium and phosphate ions at a molar ration similar to intact bone.  The hydrogel scaffold was shown to be biocompatible for selected osteogenic cells and to support proliferation and differentiation.