Find in Library

<p>Abstract</p> <p>Background</p> <p>Neutrophil gelatinase associated lipocalin (NGAL) is a highly predictive biomarker of acute kidney injury. To understand the role of NGAL in renal injury during sepsis, we investigated the temporal changes and biological sources of NGAL in a rat model of acute kidney injury, and explored the relationship between renal inflammation, humoral NGAL and NGAL expression during endotoxemia.</p> <p>Methods</p> <p>To induce acute renal injury, rats were treated with lipopolysaccharide (LPS, 3.5 mg/kg, ip), and the location of NGAL mRNA was evaluated by in situ hybridization. Quantitative RT-PCR was also used to determine the dynamic changes in NGAL, tumor necrosis factor α (TNFα) and interleukin (IL)-6 mRNA expression 1, 3, 6, 12, and 24 hours following LPS treatment. The correlation among NGAL, TNFα and IL-6 was analyzed. Urinary and plasma NGAL (u/pNGAL) levels were measured, and the relationship between humoral NGAL and NGAL expression in the kidney was investigated.</p> <p>Results</p> <p>Renal function was affected 3–12 hours after LPS. NGAL mRNA was significantly upregulated in tubular epithelia at the same time (<it>P</it> < 0.001). The course of NGAL mRNA upregulation occurred in parallel with renal damage. There was a transient increase in TNFα and IL-6 mRNA levels within 3 hours following LPS administration, and a strong correlation between TNFα and NGAL mRNA (r = 0.995, <it>P</it> <0.001) but not with IL-6 mRNA. Both pNGAL and uNGAL levels were markedly increased compared with those in the control group (<it>P</it> < 0.001); however, only uNGAL levels were correlated with NGAL mRNA (r = 0.850, <it>P</it> <0.001).</p> <p>Conclusions</p> <p>NGAL upregulation is sensitive to LPS-induced renal TNFα increase and injury, which are observed in the tubular epithelia. Urinary NGAL levels accurately reflect changes in NGAL in the kidney.</p>