[Contrast-associated nephrotoxicity: ultrastructural and biochemical study in diabetic rats]

The present study was conducted to determine whether or not the pathologic state of diabetic mellitus serves as a risk factor for the induction of nephropathy by iodinated contrast medium (CM). CM was injected into experimentally induced diabetic rats showing early diabetic nephropathy and these animals were compared with normal rats administered CM. Various types of CM were injected into diabetic rats, and nephropathy was studied morphologically and biochemically. Electron microscopic ultrastructural study revealed vacuolar formation in the cytoplasm of the proximal tubular epithelial cells (PT cells) in both groups. However, some of these changes occurred less frequently in the diabetic group. In the diabetic group, activation of glomerular mesangial cells other than PT cells was observed with amidotrizoate, and retentive deposits in the mesangial areas were found with iopamidol. Biochemical study revealed abnormal values suggesting impaired PT cells in both the diabetic and normal groups. These findings corresponded to the results of electron microscopic ultrastructural observation. The above results suggested the possible occurrence of CM-associated nephrotoxicity in the pathologic stage of diabetic mellitus, even in mild nephropathy.