BACKGROUND:Alogeneic bone marrow stromal stem cel transplantation for treatment of bone diseases is a hot topic. To seek effective methods for prevention of post-transplantation immune rejection is urgent to be solved.
OBJECTIVE:To explore the expression of MHC antigen on the surface of bone marrow stromal stem cels after osteogenic inductionin vitro.
METHODS:Bone marrow samples were extracted from rabbits to in vitro isolate and culture bone marrow stromal stem cels. Then, the cels were cultured in IMDM medium containing bone morphogenetic protein-2. Flow cytometry was used to analyze the expression of MHC antigen on the osteoblasts differentiated from bone marrow stromal stem cels.
RESULTS AND CONCLUSION:There was highly expressed MHC I antigen but no MHCII antigen on the osteoblasts differentiated from bone marrow stromal stem cels. After osteogenic induction, no immune rejection was found. These findings indicate that alogeneic or xenogeneic bone marrow stromal cel transplantation can be used in the treatment of bone defects.

BACKGROUND:Mechano growth factor has the potential to activate muscle satelite cels and promote myogenic cel growth, and has dual roles in maintaining bone mass and repairing bone defects.
OBJECTIVE: To explore the mechanism underlying osteogenic differentiation of rabbit bone marrow mesenchymal stem cels promoted by the mechano growth factor.
METHODS:The best concentration and time of mechano growth factor to promote osteogenic differentiation of rabbit bone marrow mesenchymal stem cels were detected by MTT. The mRNA and protein expressions of alkaline phosphatase and osteocalcin were detected by qPCR and western blot, respectively. The phosphorylation level of AKT and mTOR were detected by western blot assay.
RESULTS AND CONCLUSION:The best concentration and time of mechano growth factor was 45 μg/L and 5 days for promoting the osteogenic differentiation of rabbit bone marrow mesenchymal stem cels. The expressions of alkaline phosphatase and osteocalcin at mRNA and protein levels were highest after 4-hour intervention with 45 μg/L mechano growth factor, and meanwhile, the phosphorylation levels of mTOR and AKT were also highest. These findings indicate that the mechano growth factor can promote the differentiation of rabbit bone marrow mesenchymal stem cels into osteoblastsvia PI3K/AKT pathway, and its best concentration and time are 45 μg/L and 4 hours, respectively.