The Effect Of Nerve Growth Factor On New Bone Formation In The Repairment Of Mandibular Defects

Objectives In this experiment,we made models of rabbit mandibular bone defect,andimplanted nerve growth factor to bone defect area with using the gelatin sponge as thecarrier,and evaluated the effectiveness of bone formation in all respects of serology,imaging,pathology,which to study the effects of NGF on promoting new bone formationon the repair of bone defect.We hope to provide the evidence to clarify that NGF couldbe used to promote new bone formation,thus may be able to solve clinical problem suchas bone defect,bone nonunion,bone delayed union,osteoporosis,alveolarresorption andfinally reduce the invalid rate and improve quality of life.Methods15mm×8mm in one side of mandibular periosteum bone defects were madesurgically in12adult white ears rabbits which were randomly divided into NGF group(experimental group) and control group.NGF group implant nerve growth factor to bonedefect area with using the gelatin sponge as the carrier,Control group was implantednormal saline.we stitched wound at each Layer after surgery and changed dressingsdaily.The concentration of Calcium and phosphorus were examined weekly.In3and6weeks after implantation,the effectiveness of bone formation was evaluated andcontrasted by Gross anatomy observation,X-ray radiography,micro CT,HE staining andmasson three color staining.Results1.Postoperative experimental animals have no obvious signs of infection,the zone of wound healing is good,which have no obvious operation of liquid.2.The bloodcalcium of two groups were decreased beginning and then rised up to maximum valueafter two weeks,the experimental group was higher than the control group, and thedifference was statistically significant (P <0.05),then the blood calcium of each groupwere decreased gradually.The extent of the experimental group was significant, and thedifference was statistically at fifth week.The results indicated that NGF can reduceblood calcium.The blood phosphorus of two groups were decreased at the firstweek,then rised at the last four weeks,the extent of the experimental group wassignificant(P<0.05).The results indicated that NGF can promote the rise of bloodphosphates.3.Observe the index of microCT:The BMD,BV/TV,Tb.Th,Tb.N ofexperimental group were higher than the control group.While the BS/BV,Tb.Sp werelower than the control group.The difference was statistically significant(P<0.05):MicroCT3D reconstruction:the bone trabeculae of experimental group are thickerand the number are larger than the contrast group.while the gap are smaller,bone densityare higherthan the contrast group.4.Both of HE staining and masson staining show thatthe collagen and fiber were highly expressed on experimental group.5.Generalspecimens and X-ray further support above results.Conclusions The animal experiment prove that NGF can promote boneformation,which has good biocompatibility and operability and deserve application.