ObjectiveTo investigate the influences of Angiotensin Ⅱ inhibitor on renal expression of HIF-1α mRNA and protein in the chronic renal failure (CRF) rats (induced by 5/6th kidney ablation/infarction \[5/6A/I\]) and the related mechanism. MethodsSD rats were made into CRF model by means of 5/6th kidney ablation/infarction. The study was divided into sham operation group (Group A), model group (Group B) and Angiotensin Ⅱ inhibitor(Cozaar-with-Monopril) group (Group C), each group containing 15 rats. The biochemical parameters of the rats were examined 60 days later in the 3 groups. The expression of HIF-1α mRNA and protein in the remnant renal cortex and medulla were assessed by Real-time PCR and Western blotting analysis. ResultsCompared with group A, group B had significantly increased SCr and BUN levels and significantly decreased CCr level(P<0.01). Compared with group B, group C had significantly decreased SCr and BUN levels and significantly increased CCr level(P<0.05). The expression of HIF-1α mRNA and protein in the renal cortex and medulla in group B was significantly higher than that in group A(P<0.05), and that in group C was significantly lower than that in group B (P<0.05). ConclusionAngiotensin Ⅱ inhibitor can improve the renal function in CRF rats induced by 5/6(A/I), which might be associated with HIF-1α signaling pathway.