OBJECTIVETo study the relationship of renal aquaporin -1, -2, -3, and -4 (AQP1-4) expression with renal parenchymal thickness and glomerular filtration rate (GFR) in children with congenital hydronephrotis.

METHODSRenal tissue samples were obtained from 10 kidneys of 10 children (age: 62.3±18.3 months) with hydronephrosis and who underwent Anderson-Hynes pyeloplasty. Renal control samples were obtained from 6 children (age: 62.7±17.1 months) undergoing nephrectomy for nephroblastoma and were confirmed histologically as normal renal tissues. Renal parenchymal thickness of the hydronephrotic kidneys was measured by ultrasound preoperatively and was verified at operation. Renal GFR was assessed using 99mTc-DTPA scintigraphy preoperatively. Western blot was used to examine the expression of AQP1-4 in the renal tissues. The correlations of renal AQP1-4 expression with the renal parenchymal thickness and GFR were assessed by Pearson correlation analysis.

RESULTSThe expression of AQP1-4 in the hydronephrotis group was markedly reduced compared to that in the control group (P<0.05). The mean renal parenchymal thickness of the hydronephrotic kidney was 4.59±2.25 mm measured by ultrasound preoperatively. The mean GFR of the obstructed kidney was significantly lower than that of the contralateral kidney in the hydronephrosis group (40±12 mL/min vs 105±20 mL/min; P<0.05). The expression of AQP1, 2, 3 and 4 was positively correlated with preoperative renal GFR and renal parenchymal thickness in the hydronephrosis group (P<0.05). Renal parenchymal thickness was positively correlated with renal GFR (P<0.05).

CONCLUSIONSThe expression of renal AQP1-4 is reduced in children with congenital hydronephrosis. The expression levels of AQP1-4 are positively correlated with renal parenchymal thickness and GFR.