Nephrotoxicity of chromium. Remarks on an experimental and epidemiological investigation

Observations conducted on a group of workers exposed to chromium (who showed a rapid urinary excretion of the metal and progressive increase of clearance with cumulative years of exposure), induced the authors to evaluate the nephrotoxic action of chromium in rats exposed to acute and chronic intoxication. The progressive Cr accumulation in the renal cortex during the course of testing explains the increase of the excreted fraction of filtered Cr, and therefore, the clearance, of the metal through the reduction of the tubular lumen-epithelium gradient. Paralleling the anatomical lesions (demonstrated only at the level of the proximal tubular cells), are the increasing modifications of the cellular lesion or altered reabsorption registered by several urinary indicators. Similar changes were found in subjects chronically exposed to the metal; their reversibility is linked to the possibility of repairing the epithelial damage by stopping exposure.