Phenotypic change of the podocytes and expressions of paired box gene 2 and vascular endothelial growth factor in fetal lambs' kidneys with unilateral partial ureteral obstruction

Abstract

Objective To investigate the phenotypic change of the podocytes and paired box gene 2 (PAX2) and vascular endothelial growth factor (VEGF) expressions in fetal lambs' kidneys with unilateral partial ureteral obstruction. Methods Sixteen fetal lambs were randomly assigned to the obstruction and control group. The obstruction group included 12 lambs, whose superior segment ureters were tied with splited silastic tube to induce unilateral partial ureteral obstruction between 75and 85 gestational days. The control group had 4 fetal lambs subjected to sham operation. After birth,the kidneys of the lambs were harvested to study the phenotypic change of the podocytes as well as expressions of PAX2 and VEGF in the kidneys. Results Nine out of the 12 lambs of the obstruction group were delivered alive. All 4 sham operated lambs were delivered alive. Renal cortex cysts of varying sizes, interstitial fibrosis, a decrease in glomeruli number, and severe podocyte foot process fusion (4. 20± 1.08% vs 86. 79 ± 1.66%) were found in the obstructed kidneys compared with the control kidneys. The PAX2 expression in obstructed kidneys was significantly higher than that of the control kidneys (1.43 ± 0. 09 vs 2. 44 ± 0. 09, P＜0. 05). The VEGF expression was significantly decreased compared with the control kidneys (0. 80 ± 0. 15 vs 0. 33 ± 0. 14, P＜0. 05). Conclusions The changes of the phenotype and PAX2 and VEGF expressions may play roles in the pathogenesis of obstructive nephropathy. Key words: Hydronephrosis, congenital; Ureteral obstruction; Podocytes; Vascular endothelial growth factor