KIM-1 and NGAL as biomarkers of nephrotoxicity induced by gentamicin in rats

Gentamicin is a member of aminoglycosides, which has represented highly effective antimicrobial agents especially in Gram-negative infections despite their toxic effects in the kidney. Rapid diagnosis is vital to preserve renal function and to slow down renal injury. Owing to the poor sensitivity and specificity of serum creatinine (SCr) and blood urea nitrogen (BUN), new biomarkers for earlier and more accurate detection are needed. The aim of our study was to determine whether kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) may be useful biomarkers in the assessment of gentamicin-induced nephrotoxicity in rats. In this study, the two biomarkers of renal toxicity were assessed via ELISA, quantitative real-time PCR, and immunohistochemistry in rats treated with gentamicin for up to 7 days. Repeated administration of gentamicin to male SD rats for 1, 3, or 7 days resulted in a dose- and time-dependent increase in the expression of KIM-1 and NGAL. Changes in gene and protein expressions were found to correlate with the progressive histopathological alterations and preceded effects on traditional clinical parameters indicative of impaired kidney function. Both of the biomarkers are supported to be used as sensitive indicators of acute kidney injury caused by gentamicin.