The Experimental Research Of Goat Tibia Defect Repaired With Marrow Stromal Cells And Bio-derived Bone

Objective To investigate the ability of repairing goat tibia defect with tissue engineering bone constructed by marrow stromal cells (MSCs) and bio-derived bone, and the feasibility with the compound as bone substitute material. Evaluate the ability of repairing goat tibia defect with the tissue engineering bone constructed by marrow stromal cells and bio-derived bone in vitro and in vivo, and find the best way to repair large bone defect. Comparing the course of vascularization of the tissue engineering bone constructed in vitro and in vivo, and find the relationship of the bone formtion and the vascularization.Methods1. Bio-derived bone was processed as scaffold material. It was 3.0×1.0×1.0cm³.2. MSCs were harvested from goat bone marrow collected from tibial tubercle by needle aspiration and cultured in vitro. The cells were incubated at 37℃ in humidified atmosphere containing 95% air and 5% CO₂. After plating on dishes, MSCs were cultured at least for 5 to 7 days without media change to allow cell attachment to the culture dishes.3. In vitro cultured MSCs were detached from plates by trypsin(0.25%)/EDTA (0.01%) treatment and centrifuged to remove media. MSCs were coculture with the bio-derived bone in vitro.4. 12-month-old, male sheeps weighted ranging from 20 to 25 kg, were included in this study. The 20mm tibia defect model of goat was made and fixed with plate and screw.5. The blank group was not filled with anything, and the test group and the control group were filled with bio-derived bone and tissue engineering bone respectively. The repair capability for each of the treament was assessed by histopathological, X-ray, bone mineral density examinations and biomechanical examination at 2,4,6,8,12,16,24 weeks after operation.6. The bone defect model were repaired by the tissue engineering bone constructed in vitro and in vivo. The repairing ability was compared by histopathological, X-ray, bone mineral density examinations and biomechanical examination at 2,4,6,12,16 weeks after operation..7. The bone defect model were repaired by the tissue engineering bone constructed in vitro and in vivo, and the vascularization for each of the treament was assessed.Results1. No inflammatory reaction was observed in early. The defects were partially repaired with the tissue engineering bone at 8 weeks, and the defects were perfectly repaired with the engineering bone at 12,16 weeks. The effects of biomechanics had statistically significant difference between two group (P < 0.05) at 8 weeks. The effects of bone density had statistically significant difference between the test group and the control group (P < 0.05) at 8,12,16 weeks. The defects of the blank group were not repaired at 24 weeks.2. The group of the tissue engineering bone constructed in vivo degraded quickly, so was the new bone formation. The defects of this group were perfectly repaired at 16 weeks, it was faster than the group of which constructed in vivo about 2-4 weeks. But the new bone formation of group of bio-derived bone was slowly. By biomechanical examination, four groups hadn't statistically significant difference at 6 weeks (P>0. 05) .At 16 weeks, the effects of biomechanics had statistically significant difference between the groups of the tissue engineering bone constructed in vitro and in vivo(P < 0.05), so was the group of the tissue engineering bone constructed in vivo and the group of bio-derived bone(P < 0.05).3. There were almost equal number of vessels in two groups; and it hadn't statistically significant difference between the group of the tissue engineering bone constructed in vitro and the group of auto-graft(P>0. 05) . The implants were vascularized completely at 12 weeks.Conclusions 1. The 20mm tibia defect of goat can not be repaired by itself, and it has the general characters of bone defect.2. The tissue engineering bone can efficiently repair bone defect, and its repair capability is better than that of bio-derived bone alone both in quantity and quality of bone formation.3. The tissue engineering bone constructed by marrow stromal cells and bio-derived bone in vitro and in vivo can repair bone defect efficiently and quickly, but the tissue engineering bone constructed in vivo formed the new bone slowly.4. The tissue engineering bone constructed by marrow stromal cells and bio-derived bone in vitro and in vivo can vascularized quickly and completely.