CALCIUM HYDROXIDE INHIBITS SUBSTRATE ADHERENCE CAPACITY OF MACROPHAGES

The purpose of this study was to investigate the effect of calcium hyd roxide on substrate adherence capacity of rat inflammatory macrophages to determine if calcium hydroxide can alter macrophage function. Infl ammatory macrophages were obtained from Wistar rats and resuspended in RPMI-1640 medium. Substrate adherence capacity assays were carried ou t in Eppendorf tubes for 15 min of incubation at 37 degrees C in a hum idified atmosphere of 5% CO2. The adherence index (Al) was calculated. Results showed that calcium hydroxide decreased substrate adherence c apacity of inflammatory macrophages in a time and dose-dependent manne r. The lowest calcium hydroxide concentration that caused a significan t inhibition of Al was 1 mM (p < 0.05), and the concentration of calci um hydroxide that caused half-maximal inhibition (IC50) was 1.54 mM (p < 0.01). We conclude that calcium hydroxide decreased substrate adher ence capacity of macrophages. When adhesion as the first step in the p hagocytic process and in antigen presentation is taken into account, c alcium hydroxide could inhibit macrophage function and reduce inflamma tory reactions in periapical tissues or in dental pulp when it is used in root-canals therapy or in direct pulp capping and pulpotomy, respe ctively. Moreover, this effect could explain, at least in part, the mi neralized tissue-inducing property of calcium hydroxide.