THE EFFECT OF NICOTINE ON REPRODUCTION AND ATTACHMENT OF HUMAN GINGIVAL FIBROBLASTS IN-VITRO

THE ABILITY OF FIBROBLASTS TO REPRODUCE and attach to teeth is of para mount importance in re-establishing the lost connective tissue attachm ent after periodontal therapy. This study examined the effect of nicot ine, a major component of the particulate phase of tobacco smoke, on h uman gingival fibroblast (HGF) reproduction and attachment to tissue c ulture surfaces. Pooled HGF cultures made from explants of gingival bi opsies were utilized between passages 5 and 10 and plated in 96-well p lates at 1.0 x 10(4) cells per well. Cell numbers were determined usin g 3-(4,5-dimethylthiazol-2-y)-2,5-diphenyl tetrazolium bromide (MTT), which is a reflection of mitochondrial dehydrogenase activity. The con centrations of nicotine used were 0.025, 0.05, 0.1, 0.2, and 0.4 muM, the average serum concentration for a smoker being approximately 0.1 m uM. The effect of continuous nicotine exposure on HGF reproduction was determined by incubating cell cultures and media containing nicotine for up to 48 hours. Residual toxicity was determined by preincubating cells with nicotine for 1 or 6 hours. HGF suspensions and increasing c oncentrations of nicotine were added together to determine the effect on attachment. Results showed an enhanced effect of nicotine on HGF at tachment, with increasing numbers of cells attaching with increasing n icotine concentrations, compared to the control. Low concentrations of nicotine had a stimulatory effect on cell replication, while higher c oncentrations of nicotine appear to have no significant effect on HGF reproduction. The responses of cells to some concentrations of nicotin e may persist after its removal.