[Effects of different hypoxic concentrations on biological characteristics of human dental pulp stem cells in vitro].

PURPOSE: To investigate the effects of different hypoxic concentrations on biological characteristics of human dental pulp stem cells in vitro. METHODS: Impacted mandibular third molars were extracted from healthy individuals, and the dental pulp stem cells were cultured by tissue block enzyme digestion. Cells cultured under the conditions of 3%, 5% and 21% oxygen concentration for 7 days were set as 3% hypoxia group, 5% hypoxia group, and 21% nomoxia group, respectively. Flow cytometry was used to detect cell surface markers, cell cycle and apoptosis. Cell proliferation was measured by CCK-8 method. Transwell chamber assay was used to detect migration ability. Statistical analysis was completed by SPSS 20.0 software package. RESULTS: The expression rates of CD44, CD29 and D73 of the subculture cells were 97.25%, 99.36% and 99.60%, respectively. The proliferation ability of dental pulp stem cells was the strongest in 5% hypoxia group, and weakest in 3% hypoxia group, with significant difference(P<0.05). The apoptosis rate had no significant difference among various concentrations of oxygen(P>0.05). Compared with 21% nomoxia group, the proportion of dental pulp stem cells in G1 phase was significantly lower than that in 3% hypoxia group and 5% hypoxia group(P<0.05), and cell in S phase was significantly higher than that in 3% hypoxia group and 5% hypoxia group(P<0.05). The migration ability was the strongest in 3% hypoxia group, and weakest in 21% nomoxia group, with significant difference(P<0.05). CONCLUSIONS: Different concentrations of hypoxia have great influence on the morphology, proliferation, migration and cell cycle of human dental pulp stem cells in vitro with little impact on cell apoptosis.

A new AIE multi-block polyurethane copolymer material for subcellular microfilament imaging in living cells.

A multi-block fluorescent amphiphilic polyurethane copolymer (TPE-PU), self-assembling into hairy, water-soluble micelles, is used as a subcellular microfilament probe in living cells.