Egf improves recovery following relief of unilateral ureteral obstruction in the neonatal rat

Purpose: Renal epidermal growth factor (EGF) is suppressed by unilateral ur eteral obstruction (UUO), and we reported previously that exogenous EGF att enuates renal injury due to UUO in the neonatal rat. In this study, we wish ed to determine whether administration of epidermal growth factor (EGF) imp roves long-term renal cellular recovery after relief of obstruction. Materials and Methods: One ureter of 1 day-old rats was occluded or sham-op erated, and rats received daily injections of EGF, 0.1 mg./kg.,or saline fo r the following 7 days. Five days following UUO, the obstruction was remove d. Kidneys were removed 28 days following release of UUO or sham operation, and processed for histomorphometry and immunohistochemistry. Results: Kidney weight and the number of glomeruli were reduced in the post obstructed kidney regardless of administration of EGF. However, EGF reduced tubular vimentin by 36% and clusterin expression by 70% (markers of tubula r injury), and decreased tubular atrophy by 50% in the postobstructed kidne y compared with saline-treated rats. EGF also reduced interstitial or-smoot h muscle actin and interstitial collagen deposition by 50% in the postobstr ucted kidney. Conclusions: Short-term administration of EGF markedly attenuates both tubu lar and interstitial injury one month following the release of UUO in the n eonatal rat. This suggests therapeutic potential for targeted delivery of g rowth factors to optimize recovery after release of urinary tract obstructi on.