EFFECTS OF CONTRAST-MEDIA AND MANNITOL ON RENAL MEDULLARY BLOOD-FLOW AND RED-CELL AGGREGATION IN THE RAT-KIDNEY

Hemodynamic factors may play a role in the development of acute renal failure following administration of contrast media (CM). In this study the effect of intravenous injection of contrast media and mannitol on red blood cell velocity (V-RBC) and red blood cell aggregation in ren al medullary vessels was studied in j8 rats. Renal medullary blood flo w was investigated by a cross-correlation technique and by a visual ag gregation score. The CM, namely diatrizoate, iopromide, iohexol, ioxag late, iotrolan, were given in iodine equivalent doses (1600 mg/kg body wt). Mannitol (950 mOsm/liter) and Ringer's solution were used as con trols. The same vessels were studied 30 minutes before and 30 minutes after injections. V-RBC decreased significantly after injection of dia trizoate, iopromide, iohexol, iotrolan and mannitol. Ringer's solution and ioxaglate did not significantly alter medullary blood flow, while iotrolan and mannitol caused the lar est decreases in V-RBC. All CM a nd mannitol caused both red cell aggregation and cessation of blood fl ow. The decrease in blood flow and increase in red blood cell aggregat ion after injection of CIM and mannitol may partly explain the occurre nce of contrast medium-induced acute renal failure.