Association between As and Cu renal cortex accumulation and physiological and histological alterations after chronic arsenic intake

RUBATTO BIRRI, PN; PEREZ, ROBERTO D; CREMONEZZI, DAVID; PEREZ, CARLOS A; RUBIO, MARCELO; BONGIOVANNI, GUILLERMINA A.

ENVIRONMENTAL RESEARCH

Elsevier

Año: 2010 vol. 110 p. 417 - 423

0013-9351

Arsenic (As) is one of the most abundant hazards in the environment and is a human carcinogen. Prolonged ingestion of arsenic-contaminated water may result in manifestations of toxicity in practically all systems of the body (hydroarsenicism). Previous studies carried out with X-ray fluorescence spectrometry using synchrotron radiation (SR-μXRF) showed a high concentration of As in the renal cortex of rats chronically exposed during 60 days. This accumulation was accompanied by an significant increase in Cu concentration. The present study focused on the relationship between As and Cu distribution and concentration throughout the renal cortex and the nephrotoxicological process in chronically arsenic-exposed rats. Experiments were made on 12 male Wistar rats, divided into three experimental groups. Two groups received sodium arsenite at a dose of 100 µg/ml in drinking water for 60 and 120 consecutive days, respectively. Control group received As-free water (by XRF). For histological analysis, 5 µm thick sections were stained with hematoxylin and eosin. Biochemical analyses were used to determine concentrations of plasma urea and creatinine. The As and Cu mapping were carried out by X-Ray Fluorescence Spectrometry (SR-µXRF) using a collimated white synchrotron spectrum (300 ìm x 300 ìm) on kidney slices (2 mm thick) showing As and Cu co-distribution in the renal cortex. Then, renal cortical slices (100 µm thick) were scanned with a focused white synchrotron spectrum (30 µm x 30 µm) and the elemental distribution was determined. The results showed a periglomerular accumulation of As and Cu. The deleterious effects of arsenic consumption may also be seen by a decreased Bowman’s space as well as a decreased plasma BUN/creatinine ratio from 60 days of treatment, while tubular injury was seen at 120 days of exposition. Since metal accumulation, even of essential metals, may therefore be critical for that organ, this study supports the hypothesis that As-Cu accumulation in tubules may have some bearing on the early stages of the arsenic-associated nephrotoxicological process.