Tissue Distribution of Tungsten in Mice Following Oral Exposure to Sodium Tungstate

摘要

The present study describes tissue distribution of tungsten in mice following oral exposure to sodium tungstate. Mice were exposed to sodium tungstate (0, 62.5, 125 and 200mg/kg/d) for 28 days, and then kidney, liver, colon, bone, brain and spleen were harvested for trace element analysis with inductively coupled plasma mass spectrometry. The results showed increasing tungsten levels in all organs, with the highest concentration found in the bones and the lowest concentration found in brain tissue. As part of a complementary study on possible effects on immune functions from tungsten exposure, subgroups of animals were also exposed either to staphylococcal enterotoxin B or lipopolysaccharide. Immune challenge did not have significant effects on tissue distribution, and gender differences were noticed only in spleen (higher concentration of tungsten in female animals). In addition, tungsten levels in this organ were correlated with increased iron levels, something that was not observed for any other organ or either of the other two metals that were analyzed (nickel and cobalt). These findings confirmed most of what has been published on tungsten tissue distribution; they also showed that the brain is relatively protected from oral exposure, and further studies are necessary to clarify the findings on spleen.