Calcium phosphate cement attaching with recombinant human vascular endothelial growth factor and recombinant human bone morphogenetic protein-2 promotes deproteinized osteoarticular allograft to repair osteoarticular defect

Xiangyang QU; Dianming JIANG; Hong AN

ABSTRACT

BACKGROUND:

Deproteinized bone has three diamensions frame profitting bone cells to adhere to, new capillaries and interstitial cells to enter, osteoblasts to differentiate and extracellular matrix to synthesize. Calcium phosphate cement (CPC) is a new in-ceramic bone cement that can degradate, which has plasticity, no heat production, invariably mechanics intension and porosity.

OBJECTIVE:

To explore the ability of CPC attaching with human vascular endothelial growth factor (rhVEGF) and recombinant human bone morphogenetic protein-2 (rhBMP-2) in promoting deproteinized osteoarticular allograft to repair osteoarticular defect.

DESIGN:

Randomly control observation.

SETTING:

Department of Orthopaedics, the First Affiliated Hospital, Chongqing Medical University.MATERIALS A total of 42 adult hybridization dogs of both genders and weighing (10±0.5) kg were provided by Animal Center of Chongqing Medical University. RhVEGF was provided by Beijing Boaosen Biotechnology Co., Ltd.; rhBMP-2 by Guangzhou Dahui Biotechnology Co., Ltd.; CPC by Shanghai Ruibang Biotechnology Co., Ltd.

METHODS:

The experiment was carried out in the Laboratory of Orthopaedics (Municipal Laboratory), Clinical College,Chongqing Medical University from March to September 2006. A total of 36 adult dogs were randomly divided into three groups with 12 in each group, including group A CPC/rhVEGF/rhBMP-2/deproteinized femoral inferior extremity (DPB)osteoarticular allograft; group B rhVEGF/rhBMP-2/DPB osteoarticular allograft; group C simple DPB osteoarticular allograft. The experimental dogs were cut off femur by wire saw from articular surface with 30 mm, then fixed the grafts to broken ends of fractured femur with cross Kirschner wires, drawn down the proximad periosteum and sutured it. At the 4th, 8th, 12th and 16th weeks after operation, the effects were partly assessed by X-ray film examination, histologic examination as well as immunohistochemistry analysis of VEGF and BMP-2, vas capillare analysis by vaso-filling with ink, radionuclide bone imaging examination (ECT) and vitodynamic tests.MAIN OUTCOME

MEASURES:

At the 4th, 8th, 12th and 16th weeks after operation, the effects were partly assessed by X-ray film examination, histologic examination as well as immunohistochemistry analysis of VEGF and BMP-2, vas capillare analysis by vaso-filling with ink, radionuclide bone imaging examination (ECT) and vitodynamic tests.

RESULTS:

All 36 rats were involved in the final results. ① From 4th to 16th week after operation, the callus formation in group A was better than that of group B and group C by x-ray film examination. ② Image analysis system displayed that the value of area integration of optical density in group A was obviously higher than that in group B and C about VEGF at the 8th, 12th and 16th weeks, and BMP-2 at the 4th, 8th, 12th and 16th weeks. The difference had statistical significance (P＜ 0.01). ③ The new vessels of grafts in group A were more than those in group B and C, part of those inclined to mature. The difference had statistical significance (P ＜ 0.01). ④ The blood flow of operation side was higher than that of uninjured side after operation, but that in group A was significantly higher than that in group B and C. The difference had statistical significance (P＜ 0.01). ⑤ At the 16th week, the result in group A was significantly higher than that in group B and C (P＜ 0.01).

CONCLUSION:

The recombinant deproteinized osteoarticular materials have fairly strong ability of new bone formation and vasculogenesis, and can early achieve bone healing, repairing osteoarticular defect and become autologous tissue at last.