Transmission electron microscopic and X-ray absorption fine structure spectroscopic investigation of U repartition and speciation after accumulation in renal cells.
J Biol Inorg Chem
; 13(5): 655-62, 2008 Jun.
Article
en En
| MEDLINE
| ID: mdl-18273650
ABSTRACT
After environmental contamination, U accumulates in the kidneys and in bones, where it causes visible damage. Recent in vitro data prove that the occurrence of citrate increases U bioavailability without changing its speciation. Two hypotheses can explain the role of citrate it either modifies the U intracellular metabolization pathway, or it acts on the transport of U through cell membrane. To understand which mechanisms lead to increased bioavailability, we studied the speciation of U after accumulation in NRK-52E kidney cells. U speciation was first identified in various exposure media, containing citrate or not, in which U was supplied as U carbonate. The influence of serum proteins was analyzed in order to detect the formation of macromolecular complexes of U. Transmission electron microscopy (TEM) was employed to follow the evolution of the U species distribution among precipitated and soluble forms. Finally, extended X-ray absorption fine structure spectroscopy (EXAFS) enabled the precipitates observed to be identified as U-phosphate. It also demonstrated that the intracellular soluble form of U is U carbonate. These results suggest that citrate does not change U metabolization but rather plays a role in the intracellular accumulation pathway. U speciation inside cells was directly and clearly identified for the first time. These results elucidate the role of U speciation in terms of its bioavailability and consequent health effects.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Compuestos de Uranio
/
Microscopía Electrónica de Transmisión
/
Riñón
Límite:
Animals
Idioma:
En
Revista:
J Biol Inorg Chem
Asunto de la revista:
BIOQUIMICA
Año:
2008
Tipo del documento:
Article
País de afiliación:
Francia