Dynamics of intrahepatic nitric oxide (NO) using selective NO sensor during hepatic ischemia‐reperfusion in rat liver

Objective During major hepatic surgery, repetitive clamping of the hepatoduodenal ligament is necessary to reduce blood loss at the expense of hepatic ischemia‐reperfusion (IR) damage. Despite its important role, the dynamics of intrahepatic nitric oxide (NO) levels during hepatic IR has never been shown. We investigated the change of intrahepatic NO levels during IR using selective NO sensor. Methods Wistar rats were exposed to 15 min hepatic ischemia followed by reperfusion and the concentration of NO were measured using selective NO sensor. Results After starting ischemia, the intrahepatic NO levels steeply increased and reached to plateau at around 10 min. On reperfusion, the levels quickly decreased and approached to the baseline levels. By repeating 15 min ischemia followed by 5 min reperfusion, the maximum amount of NO produced during ischemia gradually decreased and almost no NO production was observed at 5th time ischemia. However, the NO production was significantly greater with 15 min reperfusion than that of 5 min reperfusion. The potential of NO production during ischemia was inversely correlated to the levels of hepatic damage evaluated by liver enzymes and tissue examination. Conclusions We firstly showed the real‐time dynamics of intrahepatic NO levels during hepatic IR using selective NO sensor. This sensor can be a useful tool in predicting hepatic IR injury during liver surgery.