Osteogenic potential of bone morphogenetic proteins-2-transfected human umbilical cord mesenchymal stem cells in vitro and in vivo

Abstract

Objective To investigate the biological characteristics of human umbilical cord mesenchymal stem cells (hUCMSC) transfected with.bone morphogenetic protein-2 (BMP-2) gene in vitro and in vivo.Methods hUCMSC were cultured in vitro.Based on the different culture media added,three groups were designed:blank group (10％ FCS/DMEM),control group (10％ FCS/DMEM + empty lentiviral particles),experimental group (10％ FCS/DMEM + BMP-2 lentiviral particles).Cell differentiation was examined by alkaline phosphatase (ALP) measurement kit.The expression of osteopontin ( OPN ),type 1 collagen ( COL1 ) and BMP-2 was detected by using Western boltting.Von kossa staining method was used to study the calcification effects. In the rat muscle bag, the complex containing BMP-2-transfected hUCMSCs/COL1 was transplanted.The ectopic bone in the implanted area was observed by the CT 3D reconstruction and hematoxylin and eosin (HE) staining.Results The positive rate of hUCMSC transfected with BMP-2 gene was (90.95 ± 4.35 ) ％.As compared with the blank group and control group,the proliferation in experimental group was promoted at 5th and 7th day after culture (P ＜ 0.05 ).The ALP activity was increased from (26.492 ±7.105) U/g·prot at 3rd day to (38.625 ± 11.592) U/g·prot at 5th day,even to (49.732 ± 13.068) U/g·prot at 14th day in experimental group as compared with other two groups (P ＜ 0.05).The COL1,OPN and BMP-2 proteins were overexpressed in experimental group,but weakly expressed in the blank group and control group ( P ＜ 0.05 ).Many mineralized nodes were observed 18 days after transfection of hUCMSC with BMP-2 gene.The ectopic bone formed in the rat muscle bag implanted with BMP-2-transfected hUCMSCs/COL1.Conclusion Transfection of BMP-2 gene can promote osteogenic potential of hUCMSCs. Key words: Bone morphogenetic protein-2; Umbilical cord mesenchymal stem cell; Osteogenic differntiation; Transfection