Hepatic ischemia induced immediate oxidative stress after reperfusion and determined the severity of the reperfusion-induced damage.

Noninvasive evaluation of organ redox states provides invaluable information in many clinical settings. We evaluated a newly developed reduction/oxidation-sensitive green fluorescent protein (roGFP) probe that reports cellular redox potentials and their dynamic changes in live cells. On hypoxia/reoxygenation (H/R) of AML12 liver cells, roGFP indicated mild reduction during hypoxia, but immediate transient oxidation after reoxygenation. The roGFP probe confirmed the antioxidative effects of N-acetylcysteine, catalase, redox factor-1, and Mn-SOD/CuZn-SOD against H/R-induced cellular oxidative stress (OS). In a mouse liver ischemia/reperfusion (I/R) model, roGFP transduced by using an adenoviral vector revealed immediate reduction of the liver under ischemia, and two distinct peaks of OS: (a) early, observed within 60 min after reperfusion, similar to the in vitro study; and (b) later, at 24 h. The early peak levels paralleled the ischemic time up to 75 min and the postischemic liver injury (sGOT/GPT/LDH) in the later phase (6 and 24 h after I/R). The roGFP probe successfully indicated postischemic OS of the liver in living mice, accurately predicting postischemic liver injury. This probe may represent an effective OS marker indicating organ redox states and also predicting the damage/function.