Blockade of Nitric Oxide Synthesis Further Diminishes Aquaporin Water Channels in Rat Kidney Subjected to Ischemia/reperfusion Injury / 대한신장학회잡지

BACKGOUND: The present study examined whether a blockade of nitric oxide (NO) synthesis affects the regulation of aquaporin (AQP) water channels in rats subjected to renal ischemia/reperfusion (I/R). METHODS: Renal I/R was experimentally induced by clamping the left renal artery for 60 minutes in rats. The rats were kept for 7 days thereafter, during which they were supplied with tap water containing NG-nitro-L-arginine methyl ester (L-NAME, 100 mg/L). The expression of AQP1-3 was determined in the kidney by Western blot analysis. RESULTS: In renal I/R injury, the expression of AQP2 was significantly decreased. The treatment with L-NAME further diminished the expression of AQP2. Although the expression of either AQP1 or AQP3 was not significantly altered in the kidney subjected to I/R, it was also significantly decreased by the treatment with L-NAME. CONCLUSION: It is suggested that endogenous NO system should play a role in the regulation of AQP water channels in rat kidney subjected to I/R injury.

Effects of Indomethacin on Aquaporin Water Channels in Rat Kidney / 대한신장학회잡지

BACKGROUND: The present study was aimed to determine whether non-steroidal anti-inflammatory drugs (NSAID) alter the regulation of aquaporin (AQP) water channels in the kidney. METHODS: Male Sprague-Dawley rats were injected with indomethacin (5 mg/kg, twice a day, i.p.) for two days. Control group was injected with vehicle. The expression of AQP1-4 proteins was determined in the kidney by Western blot analysis. RESULTS: Following the treatment with indomethacin (5 mg/kg), the expression of AQP1 was not significantly affected in the cortex and outer medulla, but was decreased and inner medulla. The expression of AQP2 was significantly decreased in the cortex, outer medulla and inner medulla. The expression of AQP3 was not significantly affected in the cortex, but was decreased in the outer medulla and inner medulla. The expression of AQP4 was detected only in the inner medulla, which was also significantly decreased. A lower dose of indomethacin (2.5 mg/kg) or diclofenac (100 mg/kg, single dose) similarly decreased the expression of AQP2. Despite the changes in AQP proteins, there were no significant changes in the expression of heat shock proteins-25 and -70. CONCLUSION: These results suggest that NSAID specifically decrease the expression of AQP water channels in the kidney.