Attenuation of injury due to unilateral renal ischemia: delayed effects of contralateral nephrectomy.

The functional abnormalities associated with unilateral postischemic acute renal failure in the rat, as produced by 60 min of complete renal artery occlusion, are influenced by the presence or absence of the contralateral kidney. When the contralateral kidney is removed prior to the ischemia, reflow of blood to the postischemic kidney is more complete. To determine whether this maneuver influenced the ultimate severity of the injury and, if so, to investigate the mechanism by which this occurred, studies were performed conjointly at Tel-Hashomer, Israel, and Chapel Hill, N.C., in uninephrectomized (UNx) and sham-operated (Sh) rats. At Tel-Hashomer, V from UNx rats was nearly double that found in Sh rats at 1 to 3, 3 to 5, and 24 hr after ischemia. By 24 hr, CCr was substantially greater in UNx rats and was similar to that from the nonischemic kidney of Sh rats. Differences in tubular function were also noted. In UNx rats, FENa at 24 hr was significantly less and TCH2O was significantly greater than the corresponding values determined in Sh rats. At Chapel Hill, by 24 hr, RBF and PGCe in UNx rats were significantly greater than the corresponding values in Sh rats, although both were less than values obtained in nonischemic kidneys. In UNx rats, RT and RPG were considerably less than the corresponding values in Sh rats and similar to the values obtained in nonischemic kidneys. Microscopic examination at 24 hr revealed widespread tubular epithelial cell necrosis in Sh rats. In contrast, tubular epithelial cell structures were preserved in UNx rats. These data indicate that substantive differences exist in the response to temporary unilateral renal ischemia, which depend in part on the absence of the contralateral kidney and which result in less severe reduction in RBF and CCr and the preservation of tubular epithelial structure and function.