[Tissue engineering vascularized bone repairing segmental femoral bone defects in rabbits].
OBJECTIVE
To investigate the effectiveness and mechanism of tissue engineering vascularized bone in repairing segmental femoral bone defects in rabbits.


METHODS
Thirty-two rabbits were randomized into two groups (n = 16 each). A segmental and critical bone defect of 15 mm in length was made at left femur. In experimental group, the tissue engineering bone constructed from autologous bone marrow mesenchymal stem cells plus beta-tricalcium phosphate (beta-TCP) and vascular bundle was implanted into bony defect. In control group, there was no implantation of vascular bundle. Animals were sacrificed at 2, 4, 8 and 12 weeks post-implantation respectively. Histological observation was conducted to determine the process of new bone formation and remodeling. The expression of vascular endothelial growth factor (VEGF) in new bone was measured by immunohistochemistry, real-time PCR and Western blot.


RESULTS
As indicated by histological observations over time, new bone formation increased in both groups. It was better in the experimental group than the control group at the beginning of 4 weeks. The expression level of VEGF gradually decreased in each group after an initial rise. And the expression of VEGF was significantly higher than the control group after implantation at all time points and peaked at 4 weeks.


CONCLUSIONS
Tissue engineering vascularized bone accelerates bone repair in critical size defect model of femur in rabbit. Implantation of vascular bundle can promote the secretion of VEGF. And VEGF is an essential mediator of both angiogenesis and ossification.
Wang
Le
L
Department of Orthopedic Surgery, Third Affiliated Hospital, Guangzhou Medical University, Third Affiliated Hospital, Guangzhou 510150, China.
Pei
Guo-Xian
GX
Gao
Liang-Bin
LB
Jiang
Shan
S
Mu
Tian-Wang
TW
Chen
Si-Yuan
SY
Qin
Jun-Jun
JJ
Jin
Dan
D
Lou
Ai-Ju
AJ
Zhao
Pei-Ran
PR
D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology; D018786:Bone Substitutes; D018483:Diaphyses / Q000293:injuries; D018919:Neovascularization, Physiologic; D010012:Osteogenesis; D011817:Rabbits; D023822:Tissue Engineering / Q000379:methods*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*; D014945:Wound Healing
D018786:Bone Substitutes; D042461:Vascular Endothelial Growth Factor A