The Experimental Study Of Calcium Phosphate Cement Mixed With BFGF And VEGF To Repair Bone Defects In Rabbit Radius

Objective:To investigate the effect of calcium phosphate cement respectively mixed with bFGF,VEGF and both of them in repairing bone defects,and to evaluate their abilities of bFGF and VEGF to repair bone defects as separate or joint application.Methods:A total of 36 rabbits(weight from 2.5 to 3.0kg) were randomly divided into four groups with 9 rabbits(18 sides of anterior limb) in each group,including goup A,B,C and D.For all rabbits 1.0 cm bone defects were created in both sides of radius.And then these bone defects region were implanted with corresponding composites:goup A was implanted with CPC only,goup B with CPC/bFGF,goup C with CPC/VEGF while goup D with bFGF and VEGF.At the 3^rd,6^th and 12^th weeks after operation 6 specimens for each group were randomly selected. The effects were partly assessed by X-ray film examination,bone mineral density measurements,biomechanical test and histological observation.Results1.Gross anatomy observation showed that at the 12^th week the bone defcts in group D were completely repaired whereas these bone defects in goup B and C were just basically repaired.However there was a few of new bone formation in group A.2.The X-ray showed that at the 12^th week the bone defcts in group D were completely repaired with CPC generally degraded,whereas these bone defects in goup B and C were just basically repaired.The BMD showed that at different time points the bone mineral density of experimental group was higher than the control group.At the 12^th week the bone mineral density of group D was significantly higher than group B and C(P＜0.05),while there was no distinct difference between these two groups(P＞0.05).3.Biomechanical testing(at the 12^th week) showed that the maximum bending load of the experimental group were significantly higher than that of the control group(P＜0.05).Group D was superior to group B and group C(P＜0.05);whereas there was no significant difference between these two groups(P＞0.05).4.Histological observation indicated that at the 3^rd week lots of trabecula and some hyaline cartilage could be seen in the experimental group.However,there were only a little of trabecula in the control group.At the 6^th week preosseous tissue had turned into woven bone in the experimental group,and the gross of new bone-formation in group D were more than group B and C.At the 12^th week,woven bone had become mature lamellar bone in group D.At the same time,the normal relation of cortical bone and marrow had resumed,and so did the normal structure of trabecula.However,the recanalizationthe of bone marrow cavity could not be seen in group B and C.And there were only a little of new bone-formation in group A.At different time points the histological score of group D was higher than group A,B and C(P＜0.05).Conclusion1.These three kinds of composite:CPC/bFGF,CPC/VEGF and CPC/ bFGF+VEGF can promote the growth of bone tissue and speed up the repair of bone defects.2.The composite of CPC/bFGF+VEGF is significantly better than the other two composites in promoting the growth of bone tissue.And it indicates that bFGF and VEGF have a synergistic effect in promoting the growth of bone tissue.