HIF-1 α, iNOS and VEGF expression of contralateral kidney during acute stage in complete ureteral obstruction of rat model

Purpose: To understand the process of hemodynamic change and compensatory hypertrophy of the contralateral kidney in an acute ureteral obstruction (UO), the inducible nitric oxide synthase (iNOS), vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1 α (HIF-1 α) expressions in the contralateral kidney were evaluated during the acute stage of unilateral UO in the rat. Materials and methods: Specimens (kidneys) were aseptically removed from 35 Sprague-Dawley rats (8 weeks old, weight 250-300gm) of the control (0 hours), sham (6, 12 and 24 hours) and experimental groups (UO 6, 12 and 24 hours). The iNOS, VEGF and HIF-1 α expressions in the contralateral kidney (total renal tissue, medulla and cortex) were evaluated by immunohistochemical staining. The HIF-1 α expression was also evaluated by a Western blot assay. Results: Contrary to the control and sham groups, the iNOS, VEGF and HIF-1 α expressions in the contralateral kidney from the immunohistochemical staining increased with time of obstruction, especially in the medulla. The HIF-1 α expression in the contralateral kidney by the Western blot assay was increased in all the renal tissue, medulla and cortex compared to those in the control and sham groups. Conclusions: In the contralateral kidneys of rats with UO increased expressions of iNOS, VEGF and HIF-1 α may facilitate trophic changes and a compensatory increase in the blood flow.