Chlorhexidine gluconate attenuates the ability of lipoteichoic acid from Enterococcus faecalis to stimulate toll-like receptor 2

Abstract

Chlorhexidine gluconate (CHX) has been widely used as a canal irrigant or an intracanal medicament on account of its antibacterial substantivity. This in vitro study aimed to determine if CHX attenuates the inflammatory activity of Enterococcus faecalis and its major virulence factor, lipoteichoic acid (LTA). An enzyme-linked immunosorbent assay showed that CHX-killed E. faecalis was less potent than heat-killed E. faecalis in the production of tumor necrosis factor alpha (TNF-alpha) by a murine macrophage cell line, RAW 264.7 (p < 0.05). Interestingly, pretreatment of LTA with 2% CHX for 6 hours or with 0.2% CHX for 24 hours almost eliminated the TNF-alpha inducibility (p < 0.05). Furthermore, CHX abrogated the ability of LTA to stimulate Toll-like receptor 2, resulting in the attenuated induction of TNF-alpha expression. Collectively, our results suggest that CHX can inactivate LTA of E. faecalis leading to the alleviation of inflammatory responses induced by E. faecalis and its LTA.