HEPARANASE EXPRESSION IN RENAL INTERSTITIAL MAY CONTRIBUTE TO EPITHELIAL AND ENDOTHELIAL CELLS INJURIES AFTER KIDNEY ISCHEMIC/ REPERFUSION EPISODE IN MICE

Abstract

Kidney ischemia/reperfusion injury (I/R) is the most frequent cause of acute kidney injury (AKI). It had been reported that epithelial and endothelial injuries occurred during kidney I/R injury. Heparanase is an enzyme that degrades glycocalyx and contributes to I/R injury in the heart and liver. This study is to elucidate the association between heparanase expression and cell injuries in kidney I/R injury. We performed kidney I/R injury model in mice using renal pedicle clamping for 30 minutes and sacrificed the mice in day 1 (n=6) after operation. Sham-operation procedure (SO, n=5) was used as control. PAS staining was used to quantify tubular injury score. Serum creatinine was measured from orbital venous. Heparanase expression was quantified using western blot and real-time PCR. Heparanase localization and endothelial injury were shown by immunostaining of heparanase and double glycocalyx-von Willebrand factor. Kidney I/R induced an increase of serum creatinine level that was accompanied by elevation of tubular injury score and glycocalyx damage. Glycocalyx damage was identified using immunofluorescent staining that revealed a disruption of glycocalyx or lectin layer in the endothelial cells of intra-renal artery. This finding was associated with significant elevation of heparanase mRNA and protein level expression. We found that heparanase was expressed in the renal epithelial and interstitial cells. In conclusion, heparanase may induce endothelial and epithelial injury in the kidney I/R episode. Using heparanase expression as a early marker of AKI may possibly promising. Keywords: kidney I/R, epithelial injury, endothelial injury, heparanase, glycocalyx