N-Acetyl-L-cysteine enhances ex-vivo amplification of deciduous teeth dental pulp stem cells

Abstract

Objective: Obtaining high number of stem cells is of interest for cell based therapies. N-Acetyl-L-cysteine (NAC) acts as a source of sulfhydryl groups and an anti-oxidative agent. The aim of this study was to test different NAC concentration on proliferation and differentiation of deciduous teeth dental pulp stem cells (DTSCs) in vitro as well as to define the possible underlining mechanism of its effect. Design: Number of viable, apoptotic and senescent DTSCs was determined after addition of NAC (0.1 mM, 1.0 mM, 2.0 mM). Also, cell cycle analysis, HIF1-alpha expression, LDH isoenzymes, superoxide-dismutase (SOD) and catalase (CAT) activity, sulfhydryl groups content, the level of lipids and proteins oxidative damage and differentiation capacity of NAC treated DTSCs was determined. Results: DTSCs expressed HIP-1 alpha in all conditions. The lowest NAC dose (0.1 mM) increased the number of DTSCs by one fifth comparing to the control, most likely stimulating entry of cells into S phase of cell cycle and enhancing the activity of LDH5 isoenzyme. The highest NAC dose (2 mM) inhibited DTSCs proliferation. Also, DTSCs had the lowest level of oxidative damage with 0.1 mM NAC. All tested NAC concentrations enhanced DTSCs osteo-chondrogenesis. Conclusion: The lowest NAC dose exerted significant positive effect on DTSCs proliferation as well as antioxidative protection creating beneficial environment for stem cells in vitro cultivation especially when their clinical use is important for stimulation of osteo-chondrogenesis.