The Regeneration Of Osseous Defect On Distal Surface Of Mandibular Molars And Effect Of GDF15 Overexpression On Bone Regeneration

Objective: The present study contained three parts.Part 1 focus on the autogenous bone graft and autogenous bone & Bio-oss graft on the regeneration of osseous defect on the distal surface of the mandibular second molar after third molar extraction.Part 2 was to explore the effectiveness and mechanism of autogenous bone,bovine porous bone mineral,used alone or in combination in regeneration of distal osseous defect of molar in dogs.Part 3 aimed at the biological effect of GDF15 overexpression on angiogenesis and osteogenesis of human osteoblast.Part ? Bone grafting using autogenous bone alone or in combination with Bio-oss in regeneration of osseous defect on the distal surface of mandibular second molar after the impacted third molar extraction: a randomized control studyMaterial and methods: A total of 94 sites in 87 patients were enrolled and random Ly assigned to 3 groups: the control group(C),the autogenous bone grafting group(Ta)and the combination of autogenous bone and Bio-oss grafting group(Tab).After surgical extraction of impacted mandibular third molar,the osseous defect on the distal surface of adjacent second molar was given the treatment according to the group assignment.The probing depth(PD),clinical attachment loss(CAL),and radiographic osseous defect depth(ODD)were measured and analyzed.Results: At postoperative 6-month and 12-month,significant reduction of ODD and PD,as well as gain of CAL were observed in the bone grafting groups compared with the control group.Moreover,the group Tab showed more stable outcome than group Ta.Part ? Comparison of autogenous bone,bovine porous bone mineral,used alone or in combination in regeneration of diatal osseous defect of molar: an experimental study in dogsMaterial and Methods: 8 adult dogs with bilateral diatal osseous defect of mandibular first molar was constructed.The defect was random Ly treated with(1)no grafting;(2)autogeous bone grafting;(3)Bio-oss + Bio-gide grafting;(4)autogenous bone + Bio-oss + Bio-gide grafting.All dogs were sacrificed at postoperative 12 weeks.The samples were underwent Micro-CT,sequencal fluorescent labeling and histological observation to detect new bone formation.Results: Micro-CT,sequencal fluorescent labeling and histological observation revealed that new bone and periodontal membrane formation were greatest in autogeous bone grafting and combination grafting group.Although Bio-oss grafting group showed comparable result to other grafting groups in Micro-CT evaluation and depth of osseous defect,the new bone and periodontal membrane formation were much less than other grafting groups,according to the result of sequencal fluorescent labeling and histological observation.Part ? The effect of GDF15 overexpression on angiogenesis and osteogenesis of human osteoblastMaterial and methods: HOB was obtained from the alveolar bone during the third molar extraction,isolated and cultured in vitro.The dose effect(0,10,20,50ng/m L)of rh-GDF-15 on rat BMSCs proliferation and m RNA expression were determined by CCK8 assay and RT-PCR.HOB was transfected by lentivirus-GDF15,and the overexpression of GDF15 was determined by real-time PCR and enzyme-linked immunosorbent assay(ELISA).Lv-GDF15-HOB was testified by CCK8 assay,apoptosis assay,alkaline phosphatase activity(ALP),calcium nodule assay,scratch assay and real-time PCR in order to detect the proliferation,osteogenesis and angiogenesis capability and the expression of vascular & osteogenic factors of HOB overexpressed GDF15.The gene expression profiles of Lv-GDF15-HOB and Lv-GFP-HOB were determined by Affymetrix gene expression microarrays.Results: 1.Rh-GDF15 had no influence on proliferation of rat BMSCs,while VEGF m RNA expression was elevated by Rh-GDF15 in a dose dependent manner,and the COX-2 expression was elevated by high dose of Rh-GDF15(50ng/m L).2.Overexpression of GDF15 exerted no influence on proliferation,apoptosis,osteogenic & angiogenic capability,osteogenesis & angiogenesis factors m RNA expression of HOB.Through the help of gene expression profile clip,no differentially expressed genes were detected according to the screening criteria.Conclusions: 1.The osseous defect distal to the mandibular second molar can not fully regenerated without bone grafting.Grafting autogeous bone alone or combined with bovine porous bone mineral can improve the periodontal status of mandibular second molar after surgery,and the combination grafting therapy has yielded the most stable outcome.2.Autogenous bone remained as golden standard material for periodontal regeneration.Grafting autogeous bone alone or combined with bovine porous bone mineral showed the most regeneration capability in distal osseous defect of molar in dogs without aberrant events.3.Overexpression of GDF15 exerted no effect on proliferation,apoptosis,osteogenic & angiogenic capability,as well as osteogenesis & angiogenesis factors m RNA expression of HOB under normoxia.Rh-GDF15 had no influence on proliferation of rat BMSCs,while the VEGF m RNA expression was elevated by Rh-GDF15 in a dose-dependent manner,and COX-2 expression was elevated by high dose of Rh-GDF15(50ng/m L).