THE DISODIUM SALT OF EDTA INHIBITS THE BINDING OF VASOACTIVE-INTESTINAL-PEPTIDE TO MACROPHAGE MEMBRANES - ENDODONTIC IMPLICATIONS

The purpose of this study was to investigate the effect of the disodiu m salt of ethylenediamine tetraacetate (EDTA), a calcium ion chelator used in the root canal therapy, on vasoactive intestinal peptide (VIP) binding to macrophage membranes (MM's). Binding assays were conducted at 15 degrees C in 0.5 ml of 50 mM Tris-HCl buffer (pH 7.5) containin g 1.6% (w/v) bovine serum albumin, 1.2 mg/ml of bacitracin, and differ ent EDTA concentrations, using 45 pM of [I-125]VIP as tracer. Results showed that EDTA inhibits VIP binding to MM's in a dose-dependent mann er, with an IC50 value of 5.4 mM (p < 0.01). EDTA concentrations equal or higher than 100 mM of abolished VIP-MM interaction. Taking into ac count that the macrophage plays an essential role in inflammatory reac tions and the immune response, we conclude that the apical extrusion o f EDTA during root canal therapy could modify VIP-macrophage interacti on modulating the inflammatory mechanisms involved in periapical lesio ns.