Injectable Magnesium Phosphate Bone Cement/Chitosan Microspheres Immobilized In Vitro Study

Objective:In this paper, through the observation of modified filling material of magnesium phosphate cement / chitosan microspheres on rabbit thoracic vertebral compression fractures of vertebral bone marrow stromal stem cells cell proliferation, platelet count, the expression of serum calcitonin, alkaline phosphatase and different concentration effects of extracts of rabbit bone marrow mesenchymal cells between MTT testing results of the fracture, so as to observe the model of thoracolumbar spine compression fracture properties of filled material, provides the experimental basis and the basis for later clinical application.Methods : Construction of 5 groups of rabbit thoracic and lumbar vertebral compression fracture of vertebral body model, 15 rats in each group, each group choose different filling materials filling, in which A group: materials(magnesium phosphate cement / chitosan)+BMP-2+IGF-1, group B: materials(magnesium phosphate cement /chitosan) +BMP-2, group C: materials(magnesium phosphate bone cement / chitosan) +IGF-1, group D: Material Group(magnesium phosphate cement / chitosan), group E: control group filled. In the model is completed, the experiment is carried out with platelet count,cell proliferation assay, MTT test, serum osteocalcin, phosphatase detection results, observed the curative effect difference, record the data and statistical analysis.Results: After the experiment, each group of platelet count with increasing extract concentration and time, is also rising. Cell proliferation experiments visible, group A(material +BMP-2+IGF-1) with time, the slow cell proliferation, cell proliferation number among the groups by analysis of variance with statistical significance(P < 0.05).Serum osteocalcin(BGP) experiments can be seen, group A(material+BMP-2+IGF-1) continuously changing with time, the content of BGP in serum increased the most obvious among the groups, serum osteocalcin by analysis of variance with statistical significance(P <0.05). Serum alkaline phosphatase test visible, group A(material+BMP-2+IGF-1) continuously changing with time, the content of serum ALP increased the most obviously, serum phosphatase content between the groups by analysis of variance with statistical significance(P < 0.05). MTT experimental results show, after 5 days of leaching, the leaching solution concentration was statistically significant differences of the mesenchymal cell MTT detection of rabbit bone marrow(P < 0.05,F=1.081, P=0.042). The concentration of extracts of value-added rate comparison, of which 25% of extract concentration added the most obvious.Conclusion; Drug osteogenic induction of BMSCs, ALP activity and osteocalcin were significantly higher than those in normal culture group(P <0.05); after the induction of BMSCs, the type I collagen, osteocalcin immunohistochemical positive. Semi quantitative RT PCR method for the determination of type I collagen m RNA, collagen type I m RNA into bone inducing culture expression was significantly higher than that of normal cultured in control group. Drug induced osteoblasts in vitro ordinary subcultured 5 passages, the cell alkaline phosphatase(ALP)activity, osteocalcin and collagen type I expression steadily maintained at a high level, maintain their osteoblastic phenotype; in co culture conditions, ALP activity, osteocalcin levels of collagen type I expression maintained at a high level, and the ALP activity, osteocalcin levels in most of the time points were higher than those of common passage culture.