Background
Renal ischemia–reperfusion injury (IRI) is a major cause of acute kidney injury and often leads to multi-organ dysfunction and systemic inflammation. Volatile anesthetics have potent antiinflammatory effects and we aimed to determine whether the representative volatile anesthetic isoflurane protects against acute kidney injury-induced liver and intestinal injury and the mechanisms involved in this protection.
Methods
Mice were anesthetized with pentobarbital and subjected to 30 min of left renal ischemia after right nephrectomy followed by exposure to 4 h of equi-anesthetic doses of pentobarbital or isoflurane. Five hrs after renal IRI, plasma creatinine and alanine aminotransferase were measured. Liver and intestine tissues were analyzed for pro-inflammatory mRNAs, histology, sphingosine kinase-1 (SK1) immunoblotting, SK1 activity, and sphingosine-1-phosphate levels.
Results
Renal IRI with pentobarbital led to severe renal, hepatic, and intestinal injury with focused peri-portal hepatocyte vacuolization, small intestinal apoptosis and pro-inflammatory mRNA upregulation. Isoflurane protected against renal IRI and reduced hepatic and intestinal injury via induction of small intestinal crypt SK1 mRNA, protein and enzyme activity and increase in S1P. We confirmed the importance of SK1 as mice treated with a selective SK inhibitor (SKI-II) or mice deficient in SK1 enzyme were not protected against hepatic and intestinal dysfunction with isoflurane.
Conclusions
Taken together, we demonstrate that isoflurane protects against multi-organ injury after renal IRI via induction of the SK1/sphingosine-1-phosphate pathway. Our findings may help to unravel the cellular signaling pathways of volatile anesthetic-mediated hepatic and intestinal protection and lead to new therapeutic applications of volatile anesthetics during the perioperative period.