In vitro inhibitory effect of EGTA on macrophage adhesion: endodontic implications

Ethylene glycol-bis-(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) is an specific calcium ion chelator proposed as endodontic irrigant. This study investigates the effect of EGTA on substrate adherence capacity of rat inflammatory macrophages. Inflammatory macrophages were obtained from Wistar rats and resuspended in RPMI-1640 medium. Substrate adherence capacity assays were carried out in Eppendorf tubes for 15 min of incubation at 37 degrees C in a humidified atmosphere of 5% CO2. The adherence index was calculated. Results showed that EGTA decreased substrate adherence capacity of inflammatory macrophages in a time- and dose-dependent manner. The EGTA concentration that caused half-maximal inhibition (IC50) was 202 +/- 32 mM (p < 0.01). EDTA was more potent than EGTA in inhibiting macrophage adherence (IC50 = 185 +/- 22 mM). Calcium chloride (10 mM) decreased the EGTA inhibitory effect on adherence index by 60.2% (p < 0.01). We conclude that EGTA significantly decreased substrate adherence capacity of macrophages.