Abstract
Uranium is a nephrotoxic heavy metal. The chronic ingestion of naturally occurring uranium in contaminated groundwater resulted in renal dysfunction related to renal tubular injury. Children are susceptible to renal damage from uranium exposure. The uranium dynamics in kidney in the developmental period, however, is poorly understood. In the present study, the dynamics of uranium distribution, localization and the surrounded tissue alteration were examined in Wistar male prepubertal rats exposed to uranium by combination of in situ determination of elements performed by μPIXE (particle induced X-ray emission) or SR-μXRF (X-ray fluorescence spectrometry using high energy synchrotron radiation) and pathological observation. The chemical form of the localized uranium in kidney was assessed by X-ray absorption fine-structure with microprobe (μXAFS).
A single injection of uranyl acetate to prepubertal rats (0.5 - 4 mg/kg, s.c.) caused tubular lesions in the S3 segment of the proximal tubules, the distal portion of the proximal tubules. μPIXE and SR-μXRF were performed for the areas covering the outer cortex to the medulla, where the S3 segment of the proximal tubules distributed. Uranium concentrated areas were detected in the epithelium of the S3 segment of the proximal tubules at the initial phase of uranium exposure. The uranium levels were 300-fold more than the mean renal uranium concentration. Regenerating and damaged tubules were observed in the restricted regions surrounded the uranium concentrated areas at the recovery phase. The time course of localized quantity of uranium, its oxidative condition, and elemental composition after uranium exposure will be presented.
