High glucose promotes the aging of human dental pulp cells through Wnt/beta-catenin signaling

Background.Diabetes is one of the most common metabolic diseases that disrupt the functioning of different body organs, including oral tissue.Some diabetic complications remain even after the control of the hyperglycemic condition.The adverse effect of hyperglycemia on the pulp structure and function has been shown previously.Objectives.The purpose of this study was to investigate the effect of the hyperglycemic state on the aging of pulp cells and evaluate the role of Wnt signaling as the underlying mechanism of this process. Material and methods.The isolated pulp cells were cultured in the Minimum Essential Medium (MEM)-alpha for 7, 14 and 21 days under the influence of glucose at concentrations of 5 mM, 20 mM and 30 mM.The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to evaluate cell viability, the beta-galactosidase test was applied to assess cellular senescence and gene expression was measured with quantitative real-time polymerase chain reaction (qRT-PCR).Results.The results of this study showed that cell proliferation decreased following exposure to 20 and 30 mM glucose, which was accompanied by an increased number of senescent cells and an increased p21 expression.There was a significant increase in beta-catenin and Wnt1 expression in response to high glucose.Treatment with beta-catenin inducer enhanced cellular aging in the hyperglycemic state, while betacatenin inhibitor decreased the senescence response.Conclusions.The present study further confirmed the effect of the high-glucose condition on pulp cell aging and suggests a role for beta-catenin in the induction of cellular aging.Targeting the key regulators of cellular aging in pulp tissue might lead to the development of new therapies for the prevention and treatment of endodontic complications in diabetic patients.