[Renal aquaporin-2 water channel expression in congestive heart failure rat].
OBJECTIVE
To study aquaporin-2 (AQP2) that mediates vasopressin-regulated collecting duct water permeability.


METHODS
Male Sprague-Dawley rats (200-250 g) underwent either a left coronary artery ligation, a model of CHF, or a shamoperation (Sham-Op). Five weeks after surgery, mean blood pressure (MBP) and cardiac output (CO) were measured by catheterization in the conscious animal. The rats were sacrificed 24 hours later. Left ventricular myocardial infarction size (LVMI) was estimated and the rats were divided into two groups according to the size of infarction. Total RNA and protein were extracted from whole kidney. AQP2 and GAPDH mRNA were measured by Northern blot and AQP2 protein expression by Western blot.


RESULTS
AQP2/GAPDH mRNA densities of Sham-Op, LVMI < 20% rats and LVMI > or = 20% rats were 1.385 +/- 0.023, 1.523 +/- 0.036, and 1.779 +/- 0.072 (P < 0.01). AQP2 protein Western blot densities were 100% +/- 10%, 157% +/- 13% and 202% +/- 25% (P < 0.01).


CONCLUSIONS
Both mRNA and protein of AQP2 gene expression are increased in CHF rat and this upregulation is present in the compensated (LVMI < 20% rats) and decompensated (LVMI > or = 20% rats) stage of CHF. This contributes to water retention associated with CHF.
Nanfang Hospital, Guangzhou.
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Xu
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Ren
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Martin
D000818:Animals; D051399:Aquaporin 2; D051403:Aquaporin 6; D020346:Aquaporins / Q000096:biosynthesis*; D015870:Gene Expression; D006333:Heart Failure / Q000235:genetics*; D007668:Kidney / Q000378:metabolism*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
C496025:Aqp2 protein, rat; D051399:Aquaporin 2; D051403:Aquaporin 6; D020346:Aquaporins