Effect of Micardis on the expression of renal medulla aquaporin-2 in diabetic mice.

In current study, the effect of angiotensin receptor blocker Micardis on the localization and expression of aquaporin-2 (AQP2) was investigated in the renal medullary collecting duct of mice with diabetic nephropathy (DN). Mice were divided into three groups: normal group, DN group and Micardis-treated group. Six weeks after establishment of STZ-induced DN model in mice, the expression of AQP2 in renal medulla was detected measured by semiquantitative immunofluorescence histochemistry and Western blot techniques, and the localization of AQP2 by confocal immunofluorescence laser scanning microscopy. The results showed that the urinary osmolality was decreased in DN group as compared with normal group (2.39+/-0.11 vs 3.16+/-0.16, P<0.05). Although the localization of AQP2 on the renal medulla was unchanged, the expression of AQP2 was increased significantly in DN group as compared with normal group. Micardis could partly attenuate above changes. It was concluded that treatment with Micardis could partly rectify the abnormal expression of AQP2 in renal medulla of DN mice, which suggested that rennin-angiotensin system (RAS) is implicated in the pathogenesis of DN by regulating the expression of AQP2.