Decreased Arsenic Disposition and Alteration of its Metabolic Profile in mice Coexposed to Fluoride.

Inorganic arsenic (iAs) and fluoride (iF) are ubiquitous elements whose coexistence is frequent in several regions of the world due to the natural contamination of water sources destined for human consumption. It has been reported that coexposure to these two elements in water can cause toxic effects on health, which are controversial since antagonistic and synergistic effects have been reported. However, there is little information on the possible toxicological interaction between concurrent exposure to iAs and iF on the iAs metabolism profile.The goal of this study was to determine the effect of iF exposure on iAs methylation patterns in the urine and the tissues of female mice of the C57BL/6 strain, which were divided into four groups and exposed daily for 10 days through drinking water as follows: purified water (control); arsenite 1 mg/L, fluoride 50 mg/L and arsenite & fluoride 1:50 mg/L.To characterize the iAs methylation pattern in concomitant iF exposure, iAs and its methylated metabolites (MAs and DMAs) were quantified in the tissues and the urine of mice was exposed to iAs alone or in combination. Our results showed a statistically significant decrease in the arsenic species concentrations and altered relative proportions of arsenic species in tissues and urine in the As-iF coexposure group compared to the iAs-exposed group. These findings show that iF exposure decreases arsenic disposition and alters methylation capacity.Nevertheless, additional studies are required to elucidate the mechanisms involved in the iAs-iF interaction through iF exposure affecting iAs disposition and metabolism.