Chlorhexidine‐Induced Changes to Human Gingival Fibroblast Collagen and Non‐Collagen Protein Production

BACKGROUND: Chlorhexidine (CHX) has been used extensively as an adjunctive therapy in the treatment of periodontal disease. It is well known that chlorhexidine is toxic to bacteria, but recent evidence has suggested that chlorhexidine may also have deleterious effects on gingival fibroblast proliferation as well as collagen and non-collagen protein production in cell culture. The purpose of this study was to examine the effects of chlorhexidine on gingival fibroblast proliferation as well as collagen and non-collagen protein production in cell culture. METHODS: Human gingival fibroblasts were incubated in MEM containing chlorhexidine concentrations ranging from 1 microM to 1300 microM at 37 degrees C for 1, 5, or 15 minutes. Control cells received an equal volume of MEM without chlorhexidine for similar times at 37 degrees C. Following incubation, the media were removed, cells washed twice with MEM supplemented with 10% FBS, and fibroblasts in treatment and control groups were allowed to recover in the same media for 24 hours. RESULTS: In all strains, cellular proliferation was dependent on the concentration of solubilized chlorhexidine in cell culture but independent of the duration of chlorhexidine exposure. The average inhibitory concentration necessary to reduce cellular proliferation by 50% (ID50) was 222.1 microM. In regard to collagen and non-collagen protein production, fibroblasts exposed to chlorhexidine concentrations (1 microM) well below the ID50 had a 65% reduction in collagen production and a 57% reduction in noncollagen protein production. CONCLUSIONS: These results suggest that chlorhexidine will induce a dose dependent reduction in cellular proliferation and that concentrations of chlorhexidine that have little effect on cellular proliferation can significantly reduce both collagen and noncollagen protein production of human gingival fibroblasts in vitro. Hence, the introduction of commercially available concentrations (0.12%) or diluted commercial concentrations (as low as 0.00009%) of chlorhexidine to surgical sites for short periods of time prior to wound closure can conceivably have serious toxic effects on gingival fibroblasts and may negatively affect wound healing.