Nicotine and N-Acetyl-L-Cysteine Effects on Gingival Fibroblast Proliferation

The use of tobacco products is a risk factor for oral disease with nicotine being a potential mediator of these pathologic effects. Nicotine can increase the rate of reactive oxygen species and free radical formation in the body. Glutathione (GSH) is a predominant defense against reactive oxygen species and free radicals in different tissues in the body. The GSH precursor, N-acetyl-L-cysteine (NAC) has been shown to increase intracellular GSH levels. Objectives: This study was designed to determine the influence of the combination of NAC and nicotine on gingival fibroblast cell proliferation: Methods: In this study, gingival fibroblasts were treated for 24 hours with NAC concentrations from 0 to 25ug/ml, nicotine concentrations from 0 to 1500ug/ml and combinations of nicotine and NAC. After 24 hours, cell proliferation was determined utilizing the colorimetric assay WST-1. Results: The data demonstrated that nicotine alone after 24 hours at concentrations of 500, 1000 and 1500ug/ml significantly decreased cell proliferation. After 24 hours, NAC alone at a concentration of 5ug/ml did not significantly reduce cell proliferation. The combination of 5ug/ml NAC and 500ug/ml nicotine after 24 hours did not significantly decrease cell proliferation. Conclusions: After 24 hours, nicotine concentrations of 500, 1000 and 1500ug/ml significantly reduced fibroblast proliferation. The combination after 24 hours of NAC at a concentration of 5ug/ml with nicotine at a concentration of 500ug/ml prevented a significant reduction in cell proliferation.