2-arachidonoylglycerol increases in ischemia-reperfusion injury of the rat liver

Several studies have implicated endocannabinoids in various forms of shock. However, the role of endocannabinoids in hepatic ischemia-reperfusion injury remains unclear. The purpose of this study was to evaluate the changes of two endocannabinoids in hepatic ischemia-reperfusion injury: anandamide (ANA) and 2-arachidonoylglycerol (2-AG). Male Sprague-Dawley rats were divided into 2 groups: the short (15 min) ischemic group and the long (60 min) ischemic group in the segmental (70%) hepatic tissue. Blood levels of aspartate transaminase (AST), alanine transaminase (ALT), lactate dehydrogenase (LDH), ANA, and 2-AG were examined. Serum levels of AST, ALT, and LDH were significantly higher in the long-ischemia group than in the short-ischemia group. Plasma levels of 2-AG showed similar augmentation prior to and after reperfusion in both the short- and long-ischemia groups, although plasma 2-AG levels tended to be higher in the long-ischemia group than in the short-ischemia group. Plasma levels of ANA were augmented in the early phase of reperfusion in the short-ischemia group and did not differ significantly from the normal level with time after reperfusion in the long-ischemia group. These results suggest that the endocannabinoid 2-AG increases in hepatic ischemia-reperfusion injury of rats, rather than ANA.