Aims: 

Renal failure is a leading cause of death at the intensive care unit and develops frequently due to ischemic acute tubular necrosis (ATN). Ischemic necrosis is followed by apoptosis during reperfusion aggravating injury. MicroRNAs (miRNA) form a gene expression regulatory network. The aim of this study was to investigate miRNA expression in renal ischemia-reperfusion (IR) injury.

Methods: 

We performed unilateral renal ischemia on the left kidneys of C57BL/6 mice and measured blood urea (Reflotron) and serum NGAL (a tubular damage marker) (ELISA) and evaluated the extent of ATN on PAS stained histological sections. We analyzed the miRNA expression profile with Luminex bead-based multiplex assay and real-time PCR technology.

Results: 

After IR injury we observed significant increase in blood urea (sham: 64.3 (25–75%: 58.3–75.4) mg/dl vs. IR: 352.8 (25–75%: 309.0–500.0) mg/dl, p<0.001) and serum NGAL levels (sham: 4.59 (25–75%: 3.39–6.17) mg/ml vs. IRI: 86.75 (25–75%: 75.38–125.59) mg/ml, p<0.001). Histology demonstrated major (p<0.001) juxtamedullary tubular cell damage compared to the sham operated group. On the Luminex multiplex platform we assayed 22 different miRNAs and identified miR-21 (2.98 fold, p<0.01) and two members of the miR-17 family: miR-106a (1.53 fold, p<0.05) and miR-17 (1.37 fold, p<0.05) with significantly elevated expression. These results were also supported by real-time PCR validation studies.

Conclusion: 

We first utilized the novel Luminex assay to identify miRNA expression profile in renal ischemia-reperfusion injury. The identified miRNAs have many potential pro-apoptotic targets (PTEN, PDCD4, and BIM), therefore miRNAs could represent possible therapeutic tools in the treatment of ischemia-reperfusion injury.

Support: 

OTKA: K81972; ETT: 011-07/2009