N-acetyl Cysteine Inhibits Cell Proliferation and Differentiation of LPSInduced MC3T3-E1 Cells Via Regulating Inflammatory Cytokines

Abstract

Background: Peri-implantitis is one of the most common complications in oral implantation and could lead to the loss of the function of bone tissues around implants. Methods: This study used lipopolysaccharide (LPS) as a stimulant for MC3T3-E1 cells and N-acetyl cysteine (NAC) as an inhibitor to inhibit the effect of LPS to investigate the effect of NAC on the expression of bone formation related factors and inflammatory related factors of osteoblasts under the action of LPS. Results: In this study, we found that the cell proliferation and cell differentiation were significantly promoted when NAC concentrations were between 0 ~ 0.5 mM, but was inhibited when the concentration exceeded 0.5 mM. LPS had a slightly promoting effect on the cell proliferation before 20 μg /mL but inhibited the cell proliferation after 20 μg/mL. LPS reduced protein and gene expressions of Runx2, ALP and BGP and increased protein and gene expressions of NF-κB and TNF-α. NAC reversibly regulated the LPS’s regulation on the expression of MC3T3-E1 cell cytokine gene and protein. Conclusion: The optimal NAC concentration for treating MC3T3-E1 cells is 0.5 mM and the optimal LPS concentration for stimulating MC3T3-E1 cells is 20 μg/mL. NAC plays an active role in regulating the differentiation of MC3T3-E1 cells, and can inhibit LPS to regulate the differentiation of MC3T3-E1 cells. NAC promotes the expression of osteogenic factor of MC3T3-E1cells and inhibits the expression of inflammatory cytokines.