The Levels And Significance Of Serum NGAL During The Ischemia-reperfusion Injury Happened In Rat Kidney

Objective: To observe the levels and significance of serum neutrophil gelatinase-associated lipocalin (NGAL) during the ischemia-reperfusion injury (IRI) happenedin rat kidney. And to discuss its function in acute kidney injury.Methods: We used well-established murine models in which the structural andfunctional consequences of brief periods of renal ischemia have been previouslydocumented. Briefly, male Sprague-Dawley (SD) rats were allocated into two groupsrandomly: sham group (group S,25), model group (group M,25). The animals wereplaced on a warming table to maintain a rectal temperature of37°C. Bilateralischemia with ARF was used in group M. After2,6,12,24, or48h of reperfusion,the animals were re-anesthetized, the abdominal cavity was opened, and about5mlblood was obtained via puncture of the inferior vena cava for measurement of NGALby enzyme linked immunosorbent assay (ELISA), the blood urea nitrogen (BUN) bydiacetylmonoxime method, and the serum creatinine (Scr) by picric acid method. Theblood samples were centrifuged for15min (3000r/min) and the supernate was storedat-70℃. The rats were killed, both kidneys were harvested, andwere fixed in10%paraformaldehyde. Then were stained with hematoxylin-eosin.Results: Compared to the sham group, the levels of serum NGAL were increased at2h and peaked at the24h samples (p <0.05), and declined a little but still had asignificant change by the48h recovery period (p <0.05). The expression of BUN waselevated at6h and peaked at the48h subgroup. The levels of Scr rised significantlyafter48h reflow (p <0.05). There were no statistical differences of serum NGAL,BUN and Scr in group S(p <0.05). The characteristic histopathologic features ofischemic injury observed by light microscope: There were a loss of brush bordermembranes, tubular dilation and luminal debris. The lumens was stenosis obviouslyby interstitial edema after12h reflow. The protein cast appear at6-h and increasedsignificantly at24h and48h.Conclusion:(1) The expression of the serum NGAL may be earlier than the Scr in ischemic renal injury. It suggests that serum NGAL may represent an early andsensitive serum biomarker for ischemic renal injury.(2) From the results we couldconclude that the function of kidney was postponed obviously compared to thechange of histopathology.