Ischemia-Reperfusion Injury in Fatty Liver Is Mediated by Activated NADPH Oxidase 2 in Rats.

BACKGROUND: Liver ischemia-reperfusion (I/R) injury is a severe complication of liver surgery, and steatosis is a risk factor for liver damage. Reactive oxygen species generated by nicotinamide adenine dinucleotide phosphate oxidase (NOX) contribute to liver dysfunction. Here we examined the role of NOX in I/R injury of fatty livers.

METHODS: Rats were fed a methionine and choline-deficient diet to induce a fatty liver. Rats then underwent surgically induced partial hepatic ischemia followed by reperfusion.

RESULTS: The overall survival rate after I/R was lower in rats with fatty livers than with normal livers (P < 0.01). Necrotic area and the concentrations of 8-hydroxy-2'-deoxyguanosine (8-OHdG), TNFα, and IL-6 were higher in fatty liver tissue than in normal liver tissue (P < 0.01). The number of p47phox-positive cells was significantly higher in fatty liver tissue than in normal liver tissue after reperfusion and peaked 24 hours after reperfusion. The number of TLR-4 positive cells was significantly higher in fatty liver tissue than in normal liver tissue after reperfusion and peaked 4 and 24 hours after reperfusion coupled with a decreased number of high-mobility group box 1-positive hepatocytes. Apocynin significantly improved the survival rate, necrotic area, and concentrations of 8-hydroxy-2'-deoxyguanosine, TNFα, and IL-6 (P < 0.01). The protective effect of apocynin on fatty livers was greater than on normal livers.

CONCLUSIONS: Ischemia-reperfusion injury was associated with increased high-mobility group box 1, TLR4, and NOX2. Inhibition of NOX activity improved oxidative stress and may prevent I/R injury in fatty liver.