[Concentration- or time-dependent manner of recombinant bone morphogenetic protein 2 in regulating expression of
Xin Cao1, Huijin Chen, Zhengli Cui
1Orthopedic Center of Shengli Oilfield Central Hospital, Dongying Shandong, 257000, P R China.
Objective:
To study biological rule of recombinant human bone morphogenetic protein 2 (rhBMP-2) in regulating the expression of vascular endothelial growth factor (VEGF) of adipose-derived stem cells (ADSCs) at different induced concentrations and time points at gene level and protein level.
Methods:
ADSCs were separated from adult human adipose tissues and cultured until passage 3. After ADSCs were induced by rhBMP-2 in concentrations of 0, 50, 100, and 200 ng/mL respectively for 24 hours, and by 100 ng/mL rhBMP-2 for 3, 6, 12, 18, 24, 36, and 48 hours (ADSCs were not induced at corresponding time point as controls) respectively, the VEGF mRNA and protein expressions were detected by RT-PCR and ELISA.
Results:
The VEGF mRNA and protein expressions induced by rhBMP-2 were concentration-dependent; the expressions were highest in a concentration of 100 ng/mL. The VEGF mRNA expression in concentrations of 50, 100, and 200 ng/mL were significantly higher than that in a concentration of 0 ng/mL (P < 0.05); and the expression in concentration of 100 ng/mL was significantly higher than that in concentrations of 50 and 200 ng/mL (P < 0.05). The VEGF protein expression in a concentration of 100 ng/mL was significantly higher than that in the other concentrations (P < 0.05). The VEGF mRNA and protein expressions induced by rhBMP-2 were time-dependent. The VEGF mRNA and protein expressions at 3 and 6 hours after induction were significantly lower than those of non-induced ADSCs (P < 0.05); the expressions were lower at 12 hours after induction, showing no significant difference when compared with those of non-induced ADSCs (P > 0.05); the expressions reached peak at 18 and 24 hours after induction, and were significantly higher than those of non-induced ADSCs (P < 0.05); the expressions decreased in induced and non-induced ADSCs at 36 and 48 hours, showing no significant difference between induced and non-induced ADSCs (P > 0.05).
Conclusion:
rhBMP-2 adjusts VEGF expression of ADSCs in a concentration- and time-dependent manner. The optimum inductive concentration of rhBMP-2 is 100 ng/mL, induced to 18-24 hours is a key period when rhBMP-2 is used to promote tissue engineering bone vascularization.
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