ABSTRACT
Objective To investigate the osteogenic ability of dextran sulfate/recombinant human bone morphogenetic protein-2/chitosan (DS/rhBMP2/CS) nano microspheres combined with coralline hydroxyapatite (CHA) in repair of segmental bone defects.Methods DS/rhBMP2/CS microspheres prepared by ionic crosslinking method were adsorbed into CHA by lyophilization.Seventy-two New Zealand rabbits were randomly divided into 3 equal groups after they had been made into models of bone defect at the right radius.The defects in the 3 groups were implanted respectively with CHA,rhBMP2/CHA and DS/rhBMP2/ CS/CHA.Another 18 animals served as a blank control group.Blood and bone samples were obtained at 4,8 and 12 weeks after implantation.The serum BGP was detected,and the bone grafts were scanned by micro-CT for calculation of volume ratio of the new bone.Hematoxylin and eosin (HE) staining was performed after bone decalcification.Results All the 72 animals recovered well without any infection or graft exposure.Gross observation at postoperative 12 weeks showed that the DS/rhBMP2/CS/CHA group was the best in the quality,quantity and strength of the new bone,as well as in the healing of bone defects.The serum levels of bone gamma-carboxyglutamic-acid-containing protein at all time points in the DS/rhBMP2/CS/CHA group were significantly higher than those in the CHA and rhBMP2/CHA groups (P ＜ 0.05).Micro-CT scanning demonstrated obvious progress in bone formation,cortical bone and marrow cavity at all time points in the DS/rhBMP2/CS/CHA group which showed significantly faster bone reconstruction synchronized with material degradation and significantly higher volume ratio of the new bone than the other 2 groups (P ＜ 0.05).Histological examinations showed better morphology of mature cortical bone and new marrow cavity at all time points in the DS/rhBMP2/CS/CHA group than in the other 2 groups.Conclusion Since DS/rhBMP2/CS/CHA possesses a better mechanism of sustained-releasing rhBMP2 to induce bone formation because of its reticular and hole-hole-connected structure,it may perform better in repairing segmental bone defects than simple CHA or rhBMP2/CHA.
ABSTRACT
Objective To evaluate the feasibilty of modified osteogenic culturing of goat adipose derived stromal cells(ADSCs).Methods From March,2013 to September,2014,platelet-rich plasma(PRP) was made from goat autogenous vein blood,and abodimoneal fat was aspirated,following aspetic procedure,primary and series passage of ADSCs was established.Osteoinduced ADSCs was carried out according to following group:combinative osteoinduction group(PRP+rhBMP-2 +ADSCs),growth factor group(rhBMP-2+ADSCs),conventional inductive group(dexamathasone+ascorbic acid + ADSCs) and noninductive group(blank group).Converted microscope was used to observe cellular pattern,cell activity,osteocalcin and collagen type Ⅰ level were detected at 1,3,5,7,9,13,17,21 days.Red Alazarin and Von Kossa staining were also assayed at different interval.Results Under observation of converted microscopy,remarkable cell proliferation with abundant ECM was noticed in combinative osteoinduction group,compared with other groups,level of cell activity,osteocalcin,collagen type Ⅰ [(0.82 ± 2.19)AU,(79.82 ± 1.36)U/L at,(78.51 ± 4.32)μ g/ml at]were significantly higher than other groups (P ＜0.05),and remarkable ALP expression and calcifed nodules were also seen.Conclusion PRP can enhance the inductive effect of rhBMP-2,and combinative osteoinduction procedure acts as a satisfactory culturing method.