Mechanisms underlying chlorhexidine-induced cytotoxicity

Chlorhexidine (CLX) is the most widely used antiseptic for wound and skin d isinfection. Despite its potent bactericidal action, skin irritation is obs erved when it is used topically. This study aimed to evaluate the mechanism s underlying CLX-induced toxicity on human dermal fibroblasts with special emphasis on factors that may mediate or counteract its undesirable effects. Cells were exposed to CLX concentrations of 0.00005-0.025% for 3, 6, 8 or 24 h in the absence or presence of different concentrations of foetal calf serum (FCS) (2, 5 and 10%). Depletion of cell ATP occurred, in a time- and concentration-dependent manner, in all experimental conditions at [CLX] >0. 001%. At 24 h of CLX exposure time, the decrease in intracellular ATP was p roduced from a 10-times lower CLX concentration (0.0001%). Concentrations g reater than or equal to0.02% produced total loss of ATP. However, cell surv ival was maintained after CLX treatment for 3 and 8 h and CLX concentration s greater than or equal to0.005% were required to produce total cell death. CLX exerted an inhibitory concentration-dependent effect on DNA synthesis from concentrations as low as 0.0001%. Only FCS at 10% appeared to have a c ytoprotective action against CLX-induced cytotoxicity. (C) 2001 Elsevier Sc ience Ltd. All rights reserved.