Effects of Cadmium on Renal Aging: A Chronic Cadmium Feeding Study in Rats

摘要

Cadmium (Cd) is known to accumulate preferentially in the renal proximal tubules. Animal and human autopsy studies have shown that damage to the renal proximal tubular cells is associated with toxicity from chronic Cd exposure. The present study was undertaken to determine if Cd exposure influences the natural aging process in the kidney and the accumulation patterns of renal copper and zinc. Male Wistar rats were treated up to 24 months with 0.0, 0.5, 5.0, and 50 mg/1 CdC12 in the drinking water. Every three months, 8 rats from each group were sacrificed to obtain kidneys from which an enriched cortical tubule preparation was extracted. Cd, zinc, and copper concentrations were determined for both the intact cortex and the tubule preparation from each rat. Changes in renal function were assessed by performing urinalysis on a regular basis. Changes in renal structure were assessed by morphometric analysis of fixed kidney sections. The levels of all three metals studied were higher in the tubules than the intact cortex indicating that these metals were concentrated by the tubular cells relative to the other cortical cell types.