Renal Morphology and Function and Urine Electrolytes in Experimental Acute Renal Failure Produced by Cyclosporine and Ischemia

Abstract

It has been difficult to produce a good animal model for cyclosporine nephrotoxicity. It has been suggested that by following 20 minutes of renal ischemia with four daily doses of cyclosporine 60 mg/kg intraperitoneally, one can create a model of reproducible renal failure. We observed excessive mortality (65%), due in part to cyclosporin's CNS effects, with these combined insults in the Munich Wistar rat. In contrast, cyclosporine alone in this dosage produced only 17% mortality and resulted in a similar degree of renal failure. Pair-fed and pair-watered vehicle and saline controls were used. The morphologic changes brought about by the castor oil vehicle of the parenteral cyclosporine solution were qualitatively similar to those brought about by cyclosporine by light microscopy, although the severity of the changes was considerably less in the vehicle-treated groups. However, by electron microscopy, pale lipid vacuoles were seen only in the cyclosporine-treated groups, whereas dense alterations in lysosomes and dilated endoplasmic reticulum also were seen in other groups. Urine sodium determined by flame photometry and urine chloride determined by Saltex reagent strips tended to be high in the initiation phase of cyclosporine-induced acute renal failure and low in the maintenance phase. In animals that developed acute renal failure following the combination of ischemia and cyclosporine, the initial urine sodium and chloride were significantly correlated with the eventual degree of renal failure. The use of Saltex urine chloride sticks in clinical urine samples showed that the readings correlated well with urine sodium and chloride determined by conventional methods, suggesting that these strips may be useful in making a quick diagnosis in the setting of acute renal failure.