The Expression And Effect Of VEGF,IGF-1 In Mandiblar Distraction Osteogensis And Bone Defect Healing.

Objective: To study the mechanism of distraction osteogenesis bycomparatively investigating the expression of vascular endothelialgrowth factor(VEGF) and insulin-like growth factor-1(IGF-1) withtwo different means of operation .Method: Twenty-eight adult dogs were randomly divided into DOgroup(12 dogs),acutely lengthening group(12 dogs)and controlgroup(4 dogs).The bilateral mandibular osteodistractionbetween the first and second molar were performed and distractedwith a rate of 1mm/day in DO group .The total lengthening was 10mm.Inthe acutely lengthening group, bilateral mandibular osteotomybetween the first and second molar were performed and fixed afterbeing acutely lengthened 10mm.The dogs of two experimental groupwere sacrificed and the regenerated bones were harvested at the sametime of the sixth day in distraction period ,the second and eighthweek of consolidation respectively for immunohistochemicaldetection of the VEGF and IGF-1.T The same region bone of controlgroup were harvested and done in the some way. In addition, thetwo experimental group were examined with X-ray at the first day ,thesecond,forth and eight week of consolidtion after completedistraction.Results: specimens macrography The incision of two experimentalgroup healed well and haven't any infection. The fixation deviceswere steady and there were regenerated bones in the osteotomy gapof all the operated animal.X-ray With the time of fixation passing,the density of new bone,inboth DO group and acutely lengthening group, was enhancedgradually.But it was higher than in DO that in acutely lengtheninggroup at the same time.Immunohistochemistry In both DO group and acutely lengthening group,A substantial increase in the expression of the VEGF and IGF-1 wasfound in the regenerated callus compared to the controls(p<0.01).The VEGF,IGF-1 was expressed in osteoblast cell,smesenchymal cell,fibroblast cells , cartilage cell and the regenerated bone matrix,the VEGF was found in the vascular endothelial cell too .At the time ofsixth day in distraction period and the second week ofconsolidation ,the expression of VEGF in DO group show higher thanthat in acutely lengthening group. Whereas the staining intensityof IGF-1 in DO group was more than that in acutely lengthening groupat the second week of consolidation.There were statistic differencebetween the staining gray of two groups (p<0.05). Finally, with thetime of consolidation elapsing, the expression of VEGF and IGF-1of the two experimental group gradually decreased.Conclusion: VEGF and IGF-1 may play important roles in thedistraction osteogenesis and bone defect healing and accelerate thenew bone regenerated .