Long-term EGF treatment partially prevents reduction of renal blood flow in response to neonatally induced partial unilateral ureteral obstruction.

Background/aims: To investigate the effects of long-term epidermal growth factor (EGF) treatment on kidney growth, renal blood flow (RBF), AQP2 expression and urine output in newborn rats with partial unilateral ureteral obstruction (PUUO).

Methods: PUUO (n = 29) and sham-operated control (CON) (n = 26) was created in 2-day-old rats. Fifteen PUUO and 14 CON rats were treated with EGF beginning from the second day after operation to 8 weeks of age. Total kidney volume (TKV) and RBF were measured by MRI at weeks 4 and 8, respectively. Urine volume and osmolality, plasma osmolality, and free water clearance were measured. Renal AQP2 expression was determined using semiquantitative immuno-blotting.

Results: PUUO induced a severe hydronephrosis and RBF reduction in the obstructed kidney which was attenuated in EGF-treated rats. Body weight, urine output and free water clearance increased, osmolality and the osmolar clearance decreased significantly in EGF-treated rats, despite unchanged AQP2 levels.

Conclusions: Long-term EGF treatment attenuated the obstruction- induced RBF reduction. Body weight, urine output increased, and urine osmolality decreased in both control and PUUO rats treated with EGF. Solute-free water clearance increased in PUUO rats which seem to be independent of AQP2 expression.