Cigarette Smoke Condensate Affects Human Gingival Fibroblasts' Proliferation and Viability

Cigarette smoke condensate (CSC), particulate matter of cigarette smoke, is comprised of thousands of chemicals (e.g. nicotine, cadmium, phenol, anthracyclic hydrocarbons, nitrosamines, heavy metals and chemical carcinogens). These chemicals are powerful inducers of inflammatory responses and are toxic to multiple cell types.  Cigarette smoking is a risk factor for periodontal disease and even promotes the development of periodontal disease.  Objective: This study investigated the influence of CSC on the proliferation and viability of human gingival fibroblasts (HGFs).  Methods: HGFs were cultured from explants of healthy gingival from crown-lengthening surgeries.  HGFs (at passage 3-12) were seeded (50,000 cells/well) in 6-well plates and exposed to 1 ml of various concentrations of CSC total particulate matter (800, 400, 200, 100, 50, 25, 12.5, 6.25, 3.125 and 0 µg/ml; Murty Pharmaceuticals, Lexington, KY) diluted in serum-free media for 72 hours.  Cell proliferation and viability were evaluated by water-soluble tetrazolium-1 (WST-1) and lactate dehydrogenase (LDH) assays, respectively.  Results: At low CSC concentrations (≤25g/ml), the HGFs remained normal in appearance.  In contrast at higher concentration (³200g/ml), the CSC-treated HGFs showed a rounded appearance with a haphazard arrangement and were detached from the 6-well plates. When the concentration of CSC reached 200 µg/ml, cell proliferation was 46.79% and decreased significantly compared to the untreated HGFs (p=0.023).  Furthermore when the CSC concentration reached 400 and 800 µg/ml, the cell proliferation was 7.32% and 6.86% (p=0.000 and p=0.000), respectively.  When the CSC concentration reached 400 µg/ml, viability was 32.42% and was significantly different than the control (p=0.001).  Moreover when the CSC concentration reached 800 µg/ml, the viability was 70.43% (p=0.000). Conclusions: CSC affects HGF cell proliferation at concentrations greater than 200 µg/ml and affects viability of HGFs at concentrations greater than 400 µg/ml.