Pre-treatment with isoflurane ameliorates renal ischemic-reperfusion injury in mice

Perioperative renal dysfunction is associated with a high mortality. The aim of this study was to investigate whether isoflurane preconditioning provides a protection against renal ischemic-reperfusion injury and whether hypoxia inducible factor 1 α (HIF-1 α) is responsible for the protection afforded by isoflurane in mice.

Adult male C57BL/6 mice received vehicle (PBS), scrambled siRNA or HIF-1 α siRNA via hydrodynamic injection through tail vein. Twenty-four hours after injection, they were exposed to 1.5% isoflurane in oxygen enriched air for 2h while controls without injection were exposed to oxygen enriched air. Twenty-four hours after gas exposure, mice were sacrificed and their kidney were harvested for western blot while other cohorts underwent renal ischemia-reperfusion injury induced by bilateral renal pedicle clamping for 25 min for renal histological or functional analysis 24h after reperfusion or by unilateral clamping for 40 min for survival rate analysis.

Survival rate and the expression of HIF-1 α and erythropoietin were significantly increased while apoptosis, renal tubule score, blood plasma creatinine and urea were decreased by isoflurane preconditioning. HIF-1 α siRNA but not scrambled siRNA injection abrogated the protective effect of isoflurane preconditioning.

Our data suggested that isoflurane preconditioning provided a protection against renal ischemic-reperfusion injury which is very likely due to hypoxia inducible factor-1 α upregulation.