Inhibition of the Activities of Matrix Metalloproteinases 2, 8, and 9 by Chlorhexidine

Abstract

Matrix metalloproteinases (MMPs) are a host cell-derived proteolytic enzyme family which plays a major role in tissue-destructive inflammatory diseases such as periodontitis. The aim of the present study was to evaluate the inhibitory effect of chlorhexidine (CHX) on MMP-2 (gelatinase A), MMP-9 (gelatinase B), and MMP-8 (collagenase 2) activity. Heat-denatured type I collagen (gelatin) was incubated with pure human MMP-2 or -9 activated with p-aminophenylmercuric acetate (APMA), and the proteolytic degradation of gelatin was monitored by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Coomassie blue staining. The effect of CHX on MMP-8 activity was also studied with a cellular model addressing the ability of phorbol myristate acetate (PMA)-triggered human peripheral blood neutrophils (polymorphonuclear leukocytes [PMNs]) to degrade native type I collagen. CHX inhibited the activities of both gelatinases (A and B), but MMP-2 appeared to be more sensitive than MMP-9. Adding calcium chloride to the assay mixtures almost completely prevented the inhibition of MMP-9 activity by CHX, while the inhibition of MMP-2 activity could be reversed only when CHX was used at a low concentration. This observation suggests that CHX may act via a cation-chelating mechanism. CHX dose-dependently inhibited collagenolytic activity of MMP-8 released by PMA-triggered PMNs. MMP-8 without APMA activation was inhibited clearly more efficiently than APMA-activated MMP-8. Our study suggests that the direct inhibition of the MMPs’ activities by CHX may represent a new valuable effect of this antimicrobial agent and explains, at least in part, the beneficial effects of CHX in the treatment of periodontitis.

Enzymatic degradation of adhesive–dentin interfaces produced by mild self‐etch adhesives

“…As the MIC of chlorhexidine, as well as of SB-3CT, is much lower than the concentration used in this study, it is probable that enzymes other than MMP-2 and MMP-9 are involved in this degradation process. For example, the role of MMP-8 might be more important than previously thought, as it is less affected by chlorhexidine (24), not affected by SB-3CT, and present in mature dentin (34). This might explain why galardine, which inhibits almost all MMPs, seems to be able to prevent degradation (6), as opposed to the SB-3CT used in our study…”

“…The resultant concentration in the hybrid layer is dependent on the specific technique used, but is probably always much higher than in our study, as a concentration of 0.002% prevents interface degradation for up to 6 months (26). Acid etching of dentin produces calcium salts and these are known to prevent the chelation-mediated inhibition of a low-concentrate chlorhexidine solution (24). This might interfere with the lower concentration of chlorhexidine used in this study.…”

“…The concentration of chlorhexidine was kept relatively low, to minimize interference with the well-balanced monomer cocktail of the self-etch adhesives. However, the chlorhexidine concentration was still higher than the minimal amount of chlorhexidine needed for complete inhibition (0.0001% and 0.002% for MMP-2 and MMP-9, respectively) (24). Another factor that might play a role in this inhibition process is the release of calcium salts through demineralization of the dentin surface.…”

Chlorhexidine increases the longevity of in vivo resin–dentin bonds

“…It has been demonstrated that chlorhexidine (CHX) solutions are capable of inhibiting MMPs (21) and reducing collagen fibril solubility in an aqueous medium (4), and that its application on acid-etched dentin does not negatively influence the immediate microtensile bond strength (lTBS) of adhesive systems to this substrate (22)(23)(24)(25). In addition to its recognized antimicrobial activity, encouraging results of recent in vivo (22,26,27) and in vitro (22,23,25,28,29) studies have demonstrated that the application of CHX to dentin between acid etching and adhesive system application seems to prevent, or at least decelerate, the degradation of collagen fibrils exposed at the bottom of the hybrid layer.…”

Wetting behaviour of silicone‐ and resin‐based root canal sealers

“…To remove smear layer, 17% EDTA solution was used, which isas the 2% chlorhexidine solutionthe concentration usually found in the endodontic literature (Zamany et al 2003, Zehnder 2006. As a final irrigation, chlorhexidine has various advantages, such as its substantivity (Rolla et al 1971, Carrilho et al 2010) and its broad antimicrobial activity (Ruff et al 2006, Arias-Moliz et al 2009, Rasimick et al 2010) and, especially when using methacrylate-based sealers, its broad-spectrum matrix metalloproteinase (MMP)-inhibiting effect (Gendron et al 1999), which can significantly improve resin-dentine bond stability (Hebling et al 2005, Mohammadi & Abbott 2009, Carrilho et al 2010. Another reason for using chlorhexidine as the final irrigant instead of NaOCl is that sodium hypochlorite has a negative effect on the shear bond strength of resin-based sealers to dentine (Nassar et al 2011).…”