Early biomarkers of renal injury and protective effect of erythropoietin on kidneys of asphyxiated newborn rats

Abstract

Background:The aims of this study were to determine which of the two biomarkers of renal injury, kidney injury molecule-1 or cystatin C, is more sensitive and to evaluate whether erythropoietin protects kidneys injured by perinatal asphyxia.Methods:Animals were split into three groups designated as follows: AE, pups that survived perinatal asphyxia and subsequently received 2.5 μg (0.1 ml) of darbepoetin (i.p.); A, the pups that survived perinatal asphyxia and received 0.1 ml of 0.9% NaCl; and C, control group. The pups were killed at different ages of life (6 h, 24 h, 48 h, 7 d, and 14 d of age; 10 rats in each subgroup). Immunohistopathological evaluation of kidneys was performed.Results:At 48 h and on days 7 and 14, absolute injury scores were significantly lower in group AE as measured by both biomarkers. Cystatin C expression was the most intensive 6 h after the hypoxic event (average value of absolute injury score was 2.82) and declined over time. Expression of kidney injury molecule-1 was less intensive, with the average value of absolute injury score being 2.02 at 6 h and 2.105 at 24 h; the peak value (2.155) was recorded 48 h after the hypoxic event.Conclusion:Erythropoietin has a protective effect on hypoxic kidneys. Cystatin C is more sensitive as an early biomarker of acute kidney injury in comparison with kidney injury molecule-1.Copyright © 2014 International Pediatric Research Foundation, Inc.