[Expression of renal aquaporin 2 after circulatory arrest]

To investigate the inhibition of renal aquaporin 2 (AQP2) and AQP2 mRNA expression due to circulatory arrest.

Forty rats were randomized into two groups. The circulatory arrest-resuscitation model was reproduced in resuscitation group (20 rats). Rats in control group were subjected to the same procedure but only received mechanical ventilation without asphyxia and resuscitation (20 rats). Rats in each group were divided into 1-hour group and 3-hour group randomly (10 rats in each group). Serum creatinine (SCr) and blood urine nitrogen (BUN) concentrations were determined in every rat. Medulla of kidney in every rat was isolated for the determination of AQP2 and AQP2 mRNA expression with Western blotting and reverse transcription-polymerase chain reaction (RT-PCR).

There were no differences in resuscitation time, SCr and BUN concentrations between resuscitation and control groups. The AQP2 protein and mRNA expression in resuscitation 1-hour and 3-hour groups were significantly decreased compared with those in control group at the same time points [protein: 38.35+/-2.08 vs. 41.06+/-1.04 (1-hour), 31.89+/-1.57 vs. 41.45+/-0.58 (3-hour); mRNA: 0.61+/-0.13 vs. 0.87+/-0.14 (1-hour),0.54+/-0.11 vs. 0.85+/-0.12 (3-hour), all P<0.01], and they were further lowered in resuscitation 3-hour group (both P<0.01).

Circulatory arrest would lead to down regulation of renal AQP2 and AQP2 mRNA expression. These changes appear earlier than those of SCr and BUN.