Expression of aquaporin-1, -2 and -4 in mice with a spontaneous mutation leading to hydronephrosis

This study investigates the expression of aquaporin-1, -2 and -4 in mice with a spontaneously-arising mutation that leads to hydronephrosis (ICR/Mlac-hydro mice). The mutant mice developed bilateral non-obstructive hydronephrosis without evidence of interstitial fibrosis or glomerulosclerosis. The mice had no abnormality in blood urea nitrogen or creatinine concentrations or in urine specific gravity. Despite the severity of the renal damage the mice grew and reproduced normally. Kidneys from the mutant mice had reduced expression of all three aquaporins compared with wild type mice. The reduction in aquaporin was proportional to the degree of hydronephrosis, but this change did not appear to be associated with disturbance of urinary function.