[Effect of sodium alginate-g-deferoxamine/chitosan microspheres on osteogenic differentiation of rat bone mesenchymal stem cells].

PURPOSE: To explore the effect of sodium alginate-g-deferoxamine/chitosan (SA-g-DFO/CS) microspheres on proliferation and osteogenic differentiation of rat bone mesenchymal stem cells (BMSCs). METHODS: A kind of SA-g-DFO/CS microsphere was developed through electrostatic interaction between porous chitosan microspheres and sodium alginate chemically grafted on the surface of DFO. Its morphology, porosity rate, pore size and sustained release of DFO in vitro were examined. Rat BMSCs were isolated and co-cultured with microspheres in osteogenic differentiation medium. MTT assay was used to study the influence of cell proliferation, and Calcein-AM/PI staining was used to observe the cell viability. Alkaline phosphatase (ALP) activity assay was conducted. PCR was used to detect the expression of genes related to angiogenesis and osteogenesis. Statistical analysis was performed using SPSS 22.0 software package. RESULTS: The SA-g-DFO/CS porous microspheres were successfully prepared with a sustained re6lease of DFO. Compared with SA/CS microspheres, the SA-g-DFO/CS microspheres were conducive to cell proliferation and differentiation, with the increases in expression level of ALP, related angiogenesis genes HIF-1α, VEGF and osteogenesis genes COLI, OCN. CONCLUSIONS: The SA-g-DFO/CS porous microspheres can provide a new choice for the development of alveolar bone regeneration.

[The role of Bmal1 in regulating the aging of mesenchymal stem cells via Wnt/ß-catenin signaling pathway].

PURPOSE: To investigate whether Bmal1 and Wnt/ß-catenin signaling pathway has synergistic or antagonistic effects on the aging of mouse bone marrow-derived mesenchymal stem cells (BMSCs). METHODS: The cells were divided into two groups. The expression of ß - catenin and TCF1 in the transfected group and the blank group were detected by real-time fluorescent quantitative PCR and Western blot. The data were statistically analyzed using SPSS 19.0 software package. RESULTS: Recombinant Bmal1 lentiviral vector was successfully constructed. The expression of ß-catenin was enhanced after Bmal1 was transfected(P<0.05), which was different from that of TCF1. There was no significant difference in TCF1. CONCLUSSIONS: Bmal1 has a synergistic effect on the aging changes of MSCs in mice directly or indirectly regulated by Wnt/ß-catenin signaling pathway.