[Preparation and property of recombinant human bone morphogenetic protein-2 loaded hydrogel nanospheres and their biological effects on the proliferation and differentiation of bone mesenchymal stem cells].
OBJECTIVE
To prepare and study the recombinant human bone morphogenetic protein-2 loaded dextran-based hydrogel nanospheres (rhBMP(2)-dex-NPs) sustained release system, and to evaluate its biological effects on cultured rabbit bone mesenchymal stem cells(BMSCs).


METHODS
The rhBMP(2)-dex-NPs were prepared by improved emulsion polymerization method. Their morphology, size and size distribution, encapsulated ratio and stability were assessed by routine procedure. Dynamic dialysis method was used to determine the release characteristics of rhBMP(2)-dex-NPs in vitro. Cell culture technique and MTT colorimetric assay were used to evaluate the proliferation and differentiation of the BMSCs, ALP kit was used to evaluate the ALP activity of the BMSCs so as to show the differentiation of the cells by adding the rhBMP(2)-dex-NPs to the DMEM culture medium (B group) or rhBMP2 only (A group). Adding dex-NPs without rhBMP2 (C group) and adding nothing (D group) were taken as the controls. The results were analyzed by statistical analysis software (SPSS10.0).


RESULTS
The shape of rhBMP(2)-dex-NPs was spherical, with a size distribution of 20 nm. The encapsulated ratio was 83% and rhBMP(2)-dex-NPs could be kept more than 6 months under 4 degrees C without decomposition , destruction or deposition. The release profile in vitro was in accordance with two phases kinetics law, and more than 80% of the encapsulated rhBMP(2) can be released during 12 days. Statistical analysis showed that rhBMP(2)-dex-NPs had biological activity, and could enhance both proliferation and differentiation of rabbit BMSCs significantly, the effect of the rhBMP(2)-dex-NPs was significantly higher than that of rhBMP(2) (P<0.01). During the first 3 days, the proliferation and differentiation of BMSCs between group A and B had no significance (P>0.05), but much faster than group C and D. After 5 to 7 days, rhBMP(2)-dex-NPs could enhance BMSCs proliferation and differentiation continually, but rhBMP2 had no enhancement any more. 7 days later, the difference between group A and B become much more significant (P<0.001).


CONCLUSIONS
The rhBMP(2)-dex-NPs can release rhBMP2 more than 12 days and have long-drawn biological effects. To encapsulate rhBMP2 into dextran-based hydrogel nanospheres may be an effective way of growth factor controlled release in tissue engineering.
Chen
Fa-ming
FM
Department of Periodontology and Mucosal Diseases, Forth Military Medical University, Xi'an 710032, Shanxi Province, China.
Wu
Zhi-fen
ZF
Jin
Yan
Y
Wang
Qin-tao
QT
Du
Yan
Y
Wang
Guo-fang
GF
D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000627:therapeutic use*; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D003692:Delayed-Action Preparations / Q000627:therapeutic use; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D036341:Intercellular Signaling Peptides and Proteins; D059630:Mesenchymal Stem Cells; D054118:Nanospheres; D011817:Rabbits; D011994:Recombinant Proteins / Q000627:therapeutic use; D016212:Transforming Growth Factor beta / Q000627:therapeutic use*
D055396:Bone Morphogenetic Protein 2; D003692:Delayed-Action Preparations; D036341:Intercellular Signaling Peptides and Proteins; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate