[Study on RhBMP-2 induced osteoporosis rat BMSCs in vitro osteogenesis and VEGF expression]

To observe the impact of bone morphogenetic protein-2 (rhBMP-2) on bone marrow stromal cells (BMSCs) osteogenesis in vitro and vascular endothelial growth factors (VEGF) expression in bone osteoporotic to prevent and treat the osteoporosis.

Twenty 6-month-old female SD rats weighted (300±20) g underwent bilateral ovariectomized. At 3 months after operation, dual-energy X-ray absorptiometry was used to measure bone mineral density of rats,the values were compared with preoperative to ensure the model successfully, and the osteoporosis rats' BMSCs were cultured by bone marrow adherent cultured and the BMSCs morphology was observed under a phase contrast microscope upside down. The osteoporosis rats' BMSCs at the 2nd generation (p2) were randomly divided into experimental and control groups and were added complete medium (containing rhBMP-2) and osteogenic induced liquid, respectively. Two weeks later, the formation of cell calcium nodules were detected by Alizarin red staining method,alkaline phosphatase activity was measured by enzyme standard instrument and the expression of VEGF was detected by RT-PCT method.

(1)Whole body bone mineral density of rats before and after operation were (0.179±0.007), (0.158±0.006) g/cm2,there was statistically significant (t=4.180,P< 0.05). (2)Alizarin red staining at 2 weeks after osteogenesis induced by BMSCs (P2) in the experimental group had more strong dyeing effect than the control group obviously. (3)Alkaline phosphatase activity at 2 weeks after osteogenesis induced by BMSCs (P2) of the experimental group (15.62±1.27) ug/gprot was significantly higher than that of the control group (8.62±0.93) ug/gprot,there was statistically significant (t=7.709, P<0.01). (4)The expression of VEGF at 2 weeks after osteogenesis induced by BMSCs (P2) of the experimental group 3.723±0.143 was significantly higher than that of the control group 0.950±0.072, there was statistically significant (t=29.462, P<0.01).

RhBMP-2 can improve the in-vitro osteogenesis ability of ovary osteoporosis rat BMSCs, promote the VEGF expression of osteogenesis factor. Regulating the VEGF expression may be one of the mechanisms of BMP-2 to participate in bone metabolism.