BACKGROUND: Acute kidney injury is a common clinical comorbidity and early diagnosis is crucial for improving prognosis, but there is still no ideal biomarker for early diagnosis.

MATERIAL AND METHODS: miRNA microarray was used for detecting miRNA in kidney subjected to renal ischemia-reperfusion injury 12 h after reperfusion. Real-time PCR was performed to validate the results of microarray. miRNAs in the ischemia group were twice as high as in the sham group. Kidney-enriched miR-10a, miR-192, and miR-194 were detected in rat plasma to screen potential biomarkers for renal ischemia-reperfusion injury. Aberrant expressed miRNA in plasma at 12 h were further detected at 1 h, 2 h, 6 h, 12 h, and 24 h to observe the changing trend of these miRNAs and were compared to blood urea nitrogen and serum creatinine.

RESULTS: Thirty-six miRNAs were aberrantly expressed in kidney of rats with renal ischemia-reperfusion injury, among which 15 miRNAs had a 2-fold greater change. Results of real-time PCR were generally in accordance with microarray results. Levels of the 15 miRNAs differentially expressed in injured kidney were not significantly different from those in sham kidney. However, miR-10a, miR-192, and miR-194 were significantly increased in plasma of rats with renal ischemia-reperfusion injury, among which miR-10a was elevated within 1 h after reperfusion, whereas miR-192 and miR-194 were elevated at 6 h after injury. Blood urea nitrogen was increased at 12 h and serum creatinine was increased at 6 h after injury.

CONCLUSIONS: Plasma miR-10a, miR-192, and miR-194 were potential biomarkers for renal ischemia reperfusion injury in rats, and miR-10a might be the most promising plasma biomarker for renal injury because of its elevation within 1 h after renal injury, as well as renal specificity.

Keywords: Acute Kidney Injury - etiology, Biological Markers - blood, Computational Biology, MicroRNAs - blood, Microarray Analysis, Real-Time Polymerase Chain Reaction, Reperfusion Injury - complications, Time Factors