Increased proliferation and adhesion properties of human dental pulp stem cells in PLGA scaffolds via simulated microgravity.

Abstract

To explore the possibility of utilizing a rotary cell culture system (RCCS) to model simulated microgravity and investigate its effects on the proliferation, adhesion, migration and cytoskeletal organization of human dental pulp stem cells (hDPSCs) on poly (lactic-co-glycolic acid) (PLGA) scaffolds. Isolated and identified hDPSCs grown on PLGA scaffolds were exposed to simulated microgravity (SMG) or normal gravity (NG) conditions for 3 days. MTT cell proliferation assays, BrdU incorporation assays, flow cytometry analysis and Western blotting were undertaken to identify the proliferation ability of hDPSCs under SMG conditions. Additionally, immunofluorescence detection, SEM observations and cell migration and adhesion assays were performed to compare adhesion, migration and cytoskeletal changes in hDPCSs subjected to SMG conditions. To further investigate the mechanisms, human pathway-focused matrix and adhesion PCR array analyses were performed. The Student's t-test was used for statistical analyses. SMG promoted proliferation and adhesion, decreased migration and reorganized the cytoskeletal organization of hDPSCs compared with the NG group. PCR array analyses revealed that following SMG treatment, ITGA6 (integrin alpha-6), ITGAV (integrin alpha-V), ITGB1 (integrin beta-1), LAMB1 (laminin beta-1) and TNC (tenascin-C) were significantly upregulated (P < 0.05). SMG may regulate the behaviour of hDPSCs grown in PLGA scaffolds in an integrin-mediated manner, which may contribute to tooth tissue engineering by increasing their expandability and scaffold adhesion.