Dental Pulp Stem Cell Conditioned Medium Reduces TEGDMA Cytotoxicity

Method: DPSCs cultures were established from extracted third molars of healthy donors 15-25 years-old. Cultures were characterized for several stem cell markers using flow cytometry. CM was collected from DPSCs cultured under serum deprivation (SD) every 4d for 24d. Each CM was enriched with 15% fetal bovine serum/FBS prior to the exposure to the cells. Moreover, each FBS-enriched CM was diluted with normal (aMEM+15% FBS) medium so that three concentrations (25, 50 and 75%) of CM were tested for their impact on TEGDMA-induced cytotoxicity. Cytotoxicity of TEGDMA (0.25, 0.5, 1.0 and 2.0mM) on DPSCs with or without the presence of CM was tested by MTT and in vitro scratch assay (n=3).  

Result: DPSCs cultures were strongly positive (>95% of the population) for CD90, CD81, CD49f, nestin, Nanog and partly for CD105 (75%), CD146 (57%), STRO-1 (4.3%), CD24 (4.8%), Oct3/4 (25%), CD271 (2.5%). CD45, CD34, SSEA-3 and TRA-1-60 were not expressed. Our results showed that DPSCs’ CM (mostly after 4d and 8d of SD) was able to increase cell proliferation in DPSCs cultures compared to control cultures without CM by 20-25% and to reduce TEGDMA cytotoxicity (by approx. 20% at all concentrations, except 2mM). The effects of CM were more robust at the 50% concentration, whereas the 25 and 75% concentrations had a lower effect. In vitroscratch assay showed an overall increase in migration rate in TEGDMA-treated cultures exposed to 50% CM compared to cultures treated only with TEGDMA.    

Conclusion: These findings suggest that DPSCs paracrine effects expressed through their CM, is able to significantly increase cell proliferation and to reduce TEGDMA cytotoxicy. These data give evidence on the potential role of DPSCs’ paracrine effects on pulp repair processes.