Analysis of proteinuria in experimental model of ascending acute kidney injury

Proteinuria accompanies kidney diseases of various etiology and correlates with the degree of organ damage. Analysis of proteinuria allows the location of pathophysiological process in the kidney, and assessment of the severity of the kidney disease in chronic and acute kidney injury (AKI). Ascending bacterial acute kidney injury develops as a consequence of pyelonephritis. It is a rare complication in patients with anatomical or functional dysfunctions of the urinary tract.

The aim of the study was to perform the laboratory analysis of proteinuria in bacterial ascending AKI in an experimental model.

Female Wistar rats (n = 24) were intravesically administrated bacterial suspension of Escherichia coli (E. coli) to induce: pyelonephritis (group 1, 10⁵ CFU/ml); AKI (group 2, 10⁷ CFU/ml); AKI and urosepsis (group 3, 10⁹ CFU/ml) respectively. Bacterial strain - E.coli, was isolated from a patient with acute pyelonephritis. The daily diuresis and urine protein excretion was measured the following days: 0, 7, 14 and 21. Moreover, electrophoretic separation of urine protein, densitometric analysis of albumin fraction and uromodulin concentration in urine were performed. Moreover, the key parameters for the diagnosis of AKI were assayed.

Increased urinary protein excretion was observed in each of the study groups. Moreover, the study groups showed significant changes in protein selectivity in the urine.

Moderately severe proteinuria was revealed while its selectivity suggested significant damage of glomeruli and renal tubules in groups with complications caused by AKI induced by ascending pyelonephritis.