Effects Of Nerve Growth Factor On Bone Regeneration In Rabbit’s Model Of Distraction Osteogenesis

Objective:Our study aimed to investigate the effect of locally applied exogenous nerve growth factor (NGF) on the distraction osteogenesis of rabbits. Then estimate the feasibility of shorten the period of the bone healing and fixed time after operation.Methods:Nine New Zealand white rabbits were used in the study to establish bi-mandible distraction osteogenesis models. The local injection of1.0μg NGF was given on one side of the mandible randomly as experimental group once a day for five days. At the same time, normal saline was injected on the other side as control group as the same dose and same time. Every three rabbits were sacrificed at2,4and8weeks respectively. The mandible samples were prepared and examined for x-rays, distance and diameter measurement, general observation, HE staining and bone histology analysis.Results:The soft tissue was full of the gap of distraction osteogenesis and the density of the new bone in the area of distraction osteogenesis at2and4weeks was lower than normal bone. Compared with the control group, the quantity of new bone was increased in the experimental group. The new bone density in both groups was similar to the experimental and normal group at8weeks. There was not obvious difference in the density and distance and diameter of new bone bettween the experimental and control group, but the fabrous issue was reduced and the Trabecular bone was increased with the extension of the fixed time. The quantity of new bone was significantly different between experimental and control group at2and4weeks, but similar at8weeks. The bone volume/total volume (BV/TV) was higher than the control group (p<0.05) at2and4weeks. In the experimental group, the haversian system was observed, in contrast, the control group was combined with woven bone at8weeks. The bone volume/total volume was no distinct (p>0.05).Conclusions:Applying exogenous NGF in the early phase could accelerate the formation and maturation of trabecular bone in the area of distraction and shorten the period of fixed stage. Nerve growth factor could promote bone regeneration in the early stage of distraction osteogenesis, and shorten the period of the bone healing and fixed time after operation.