Objective: To prepare a composite membrane by chitosan/β-sodium glycerophosphate(CS/β-GP) thermosensitive hydrogel combined with stromal cell derived factor-1(SDF-1) and observe its biological characteristics in vitro. Methods: Different doses of SDF-1 were added into CS/β-GP solution and then the thermosensitive gel time was measured. The SDF-1/CS/β-GP solution was membrane paved and dried to prepare composite membranes. The morphological characteristics were observed by scanning electron microscope(SEM). Composite membranes were placed into cell culture medium, and the supernatant(n=3) was extracted after standing at 6, 12, 24, 36, 48, 60 h, respectively. The concentration of SDF-1 in the solution was measured. Bone mesenchymal stem cells(BMSCs) were cultured in the Transwell room, and the composite membranes containing different concentrations of SDF-1 were placed in the lower chamber. There were four groups(n=3): Group M0 used CS/β-GP membrane(control group), Group M1, M2, M3 used SDF-1/CS/β-GP membrane(SDF-1 was 100, 200, 400 ng/mL respectively). After culture for 6, 12 and 24 h, the cells under the membrane were preserved and Giemsa stained and counted. The absorbance(OD) value was measured by MTT method to calculate the cell proliferation rate. SPSS 19.0 was used for multi-factor analysis of variance. Results : After adding a certain amount of SDF-1 into CS/β-GP solution, the gel time did not change significantly(P>0.05). The SDF-1/CS/β-GP membrane was translucent and porous at 37 ℃. In this experiment, the volumic mass of SDF-1 released by SDF-1/CS/β-GP composite membrane increased gradually with the experimental time(P<0.01). Transwell cell chemotaxis test showed that the number of BMSCs cells with directional migration increased with the prolongation of observation time(P<0.01) and the increase of SDF-1 volumic mass(P<0.01). In MTT test, the OD value of migration cell solution increased with the prolongation of time(P<0.01) and the increase of SDF-1 volumic mass(P<0.01). Conclusion The SDF-1/CS/β-GP composite membrane has a porous structure and biological activity of chemotactic BMSCs directional migration. It is a potential membrane for guided tissue regeneration.

Objective: The aim of this study is to investigate the roles of Notch signaling and autophagy on mineral trioxide aggregate (MTA) induced differentiation of human dental pulp cells (hDPCs). Methods : Third molars from healthy human were collected and hDPCs were isolated by a combined digestion of collagenase Ⅰ and dispaseⅡ. Real time PCR were used to test the mRNA expression levels of alkaline phosphatase (ALP), runt-related transcription factor 2 (Runx2) and dentin sialophoprotein (DSPP) in MTA treated hDPCs in different time (24 h, 3 d and 7 d). The mineralization nodules formed by hDPCs with or without MTA treatment were detected by Von Kossa staining. Expressions of Notch1, Jagged1, Hes1, LC3Ⅱ/LC3 Ⅰand p62 in wild type and MTA treated hDPCs were detected by western blotting. Results: MTA extracted in a concentration of 0.1 mg/mL could promote the differentiation of hDPCs. Compared with that of wild type hDPCs, the expressions of Notch1, Hes1, or Jagged1 and p62 (P<0.01) in MTA treated hDPCs were significantly increased. MTA treatment showed inhibition effects on autophagy flux similar to Bafilomycin A1, a specific inhibitor of fusion between autophagosomes and lysosomes. Conclusion MTA could promote hDPCs differentiation with highly relevant in stimulating Notch1-Jagged1-Hes1 signaling and inhibition of autophagy flux.