| Objective: To evaluat the level and significance of urinary interleukin-18(IL-18)withacute kidney injury(AKI)in rat after the ischemia-reperfusion injury(IRI)．Methods:1.Group Fifty healthy male Sprague-Dawley (SD) rats were allocatedinto two groups randomly: Sham group (group S, n=25), model group (groupM,n=25).2.Developing animal model They were free to water without food12hours before the experiment, weighted and recorded the weight of every rats. Theanimals were anesthetized with20%urethane (5ml/kg intraperitoneally) and placedon a warming table to maintain a rectal temperature of37°C. Bilateral ischemia withAKI was used in group M, and both renal pedicles were occluded with a nontraumaticvascular clamp for30min, during the kidneys were kept warm and moist. When theclamps were then removed, the kidneys were observed for return of blood flow, andthe incision was sutured. The mice were allowed to recover in a warmed cage, andtimed urine.3.Collecting Samples Respectively at time point of2,6,12,24, or48hpost reperfusion in different groups, when the animals were re-anesthetized and theabdominal cavity was opened, urine samples Separately were collected via bladderpuncture,centrifuged for10minutes (3000r/min) and stored at-70℃for later use.Blood samples were drawn from inferior vena cava, centrifuged for15min(3000r/min) and stored at-70℃for later use. Then the rats were killed and bothkidneys of rats were removed and saved in10%formaldehyde solution in order toobserve histological changes.4. The expressions of urinary IL-18were measured byenzyme linked immunosorbent assay (ELISA) method and the blood urea nitrogen(BUN) by diacetylmonoxime method, but the serum creatinine (SCr) were detectedby picric acid method. Paraffin sections were stained with hematoxylin-eosin andexamined histologically by light microscope.Results:1. Compared with group S, the levels of urinary IL-18in group M wereincreased at6h and reached the peak at12h(p <0.05), then decreased a little but alsohad a significant change by the48h recovery period (p <0.05). The expression ofBUN was elevated at6h and peaked at48h. The levels of SCr rised significantly after 48h reflow (p P<0.05). There were no statistical differences of urinary IL-18,serumBUN and SCr in group S (p>0.05).2. The characteristic histopathologic features of ischemic-reperfusion injury:①macroscopic observation: In group S,the kidney seems normal and the color wasruddy after split lengthways. In group M,the kidney appearance was dark red and thevolume was swelling, and there was scattered hemorrhage in fragments in some ofthem. The color was pallor in kidney cortex and dark red in medulla after splitlengthways.②Observation 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 at6h.Conclusion:1. The level of BUN in group M was elevated at6h and reached a higherlevel gradually with time,but the levels of SCr rised significantly after48h reflow.2. The characteristic histopathologic features of renal ischemia-reperfusion injury inrats induce pathological changes in renal interstitial damage and tubular epithelialcells,which are in line with the pathological features of acute kidney injury.3. The expression of urinary IL-18may be earlier than the SCr inischemic-reperfusion renal injury. It suggests that urinary IL-18represent an earlybiomarker for acute kidney injury. |
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