EFFECT OF CHRONIC FLUORIDE EXPOSURE IN UREMIC RATS

This study was conducted to test the hypothesis that the margin of saf e fluoride exposure is narrowed in rats that are physiologically compr omised by renal dysfunction. The study objective was to determine whet her increases in fluoride retention and tissue fluoride levels in rats with surgically induced renal insufficiency result in toxic fluoride effects not ordinarily observed in healthy animals. Uremic and sham-op erated control rats received 0 mu g/ml, 5 (0.26 mmol/l), 15 (0.79), or 50 mu g/ml (2.63 mmol/l) of fluoride in their drinking water for 3 or 6 months. Fluoride retention was monitored, and, following euthanasia , tissue fluoride and biochemical markers of tissue function were anal yzed. Selected tissues were saved for histology, and bone marrow cells were harvested for determining the frequency of sister chromatid exch ange, a marker of genetic damage. In spite of significantly higher lev els of fluoride in the tissues of the animals with renal insufficiency , there were no clinically adverse, fluoride-induced, extraskeletal ph ysiological, biochemical, or genetic effects of chronic exposure to co mmon levels of fluoride in these rats.