OBJECTIVEBone marrow stromal cells (MSCs) were transfected with human bone morphogenetic protein-4 (hBMP-4) gene in vitro to provide BMP gene modified cells for tissue-engineered bone.

METHODSMSCs were cultured and transfected with pEGFP-hBMP4, pEGFP plasmids respectively or left uninfected as control. Transcription of BMP-4 gene as well as gene transfection efficiency was tested. Morphological and growth feature of the transfected cells were valued. Alkaline phosphatase (ALP), von Kossa, and Osteocalcin (OC) were tested to determine the phenotypes of osteoblast.

RESULTSThe gene transfection efficiency was 20%-30%, based on GFP expression. RT-PCR showed that MSCs had low transcription of BMP-4 that was enhanced by the gene transfer. Morphological feature of MSCs transfected with pEGFP-hBMP-4 changed but growth curves did not show much difference among the groups. In pEGFP-hBMP-4 group, ALP positive stain area and the number of calcium nodules were increased, as well as the expression of OC.

CONCLUSIONSA high transfer efficiency of MSCs was achieved under optimized conditions. The gene transfer technique strengthened the transcription of BMP-4 and promoted differentiation from MSCs to osteoblasts. hBMP-4 transferred MSCs may serve as an ideal cell source for tissue-engineered bone.