Abstract

To assess the renal effects of fluoride, isolated rat kidneys were perfused in single pass mode for 120 min. Five, 15 and 50, as well as 150, 500 and 1500 mumol NaF were administered 60, 80 and 100 min after starting the perfusion, respectively. Kidneys were perfused with constant pressure (100 mmHg). The perfusate consisted of a substrate supplemented Ringer solution containing hydroxy ethyl starch (HES) to produce isoncotic conditions. Concentrations below 500 mumol/l NaF did not induce major changes in the main parameters of renal function. Only upon admixture of the highest concentration of 1500 mumol/l NaF severe changes in renal function could be observed, resulting in complete anuria and a drastic reduction of renal perfusion to 5% of control, associated with a cessation of glomerular filtration. Due to the lack in tubular load, tubular reabsorptive processes inevitably declined to zero. The morphological analysis of kidneys exhibited to 500 mumol/l NaF revealed the occurrence of vesicular material within the urinary space. These vesicles could electron microscopically be identified as membrane enclosed material of podocytic origin. The interstitium was widened. Upon admixture of 1500 mumol/l NaF, kidneys responded with a decrease of the interstitial space. Moreover, epithelial cell swelling, hydropic degeneration of all proximal and distal tubular segments, bleb formation and intraluminal casts were observed frequently. Glomerular capillaries were filled with fine precipitates and their endothelium was severely damaged. The results of our studies in the isolated perfused rat kidney (IPRK) model clearly demonstrate a direct dose dependent acute nephrotoxic effect of NaF only for extremely high doses, which, however, may be reached in human cases of severe fluoride intoxication. On the contrary, for low fluoride doses, especially for those concentrations occurring in human plasma upon cariesprophylactic intake of fluorides, no signs of direct acute nephrotoxic action could be observed in the IPRK model.

• Related Studies :

  • Evaluation of serum lipoprotein and tissue antioxidant levels in sheep with fluorosis

    The aim of this study was to evaluate serum lipoprotein and tissue antioxidant levels of sheep with and without fluorosis living in a volcanic area of Turkey. Fifteen Akkaraman sheep with fluorosis in the A?ri region north of Lake Van and 10 Akkaraman sheep without fluorosis in the Van region

  • Studies on serum fluoride and bone metabolism in patients with long term hemodialysis

    With growing experience of the long-term treatment of patients with end stage renal disease by hemodialysis, the safety of fluoridated water supply for dialysate and the effect on the bone metabolism has been discussed. In this study, concentrations of fluoride (F), calcium (Ga). aluminum (AI) and biochemical indices of bone metabolism,

  • Protective effects of vitamin C against fluoride toxicity.

    Fluorine is a highly toxic substance that is widely distributed with drinking water and nutrients. While fluorine is not free in nature, it can form compounds with almost all metals and nonmetals except oxygen and inert gases. Fluorine is found in the environment in water, soil, air, nutrients, and vegetation

  • Studies on the DNA and RNA contents of heart, liver and kidney of rats with chronic fluorosis

    17 rats with chronic fluorosis induced by prolonged drinking of water containing 50 ppm fluorine and 17 rats drinking low-fluorine water served as control were used to study the DNA and RNA contents of heart, liver and kidney. The findings suggest that excessive accumulation of fluorine can suppress the synthesis

  • Effect of sodium fluoride on concentrating and diluting ability in the rat

    Mechanisms for the concentrating defect produced by fluoride were examined in the rat. Free-water clearance at all levels of delivery was normal after 5 days of chronic fluoride administration in the hereditary hypothalamic diabetes insipidus rat. In the Sprague-Dawley rats, during moderate fluoride administration (120 micronmol/kg per day), urine osmolality