Reperfusion liver injury-induced superoxide dismutase and catalase expressions and the protective effects of N-acetyl cysteine

Aim. Reperfusion of the ischemic liver results in the generation of oxygen radicals. In this study, we analyzed if the mRNA and protein expressions of superoxide dismutase (SOD) and catalase increased after ischemia (1) and reperfusion (R) of the rat liver. Materials and methods. Ischemia was induced by clamping off the common hepatic artery and portal vein of rats for 40 minutes, which were then reperfused for 90 minutes. Blood samples collected prior to I and after R were analyzed for hydroxyl radical (center dot OH), nitric oxide (NO), and alanine transferase (ALT). Liver tissues were used to analyze the SOD and catalase mRNA and protein expressions by real-time polymerase chain reaction and Western blot. Results. The results showed that this protocol resulted in elevation of the blood ALT, NO, and center dot OH levels (P <.001). mRNA (P <.01) and protein expressions (P <.05) of SOD and catalase were all increased. Pretreatment with antioxidant, N-acetyl cysteine, attenuated the liver injury. Conclusion. These results indicate that reperfusion of the ischemic liver induced antioxidant enzymes expressions so that oxygen radicals are scavenged. Oxygen radical scavenger could further attenuate the I/R-induced liver injury.