Activities, electrophoretic profiles and immunolocalization of superoxide dismutase in human liver specimens

In order to elucidate active oxygen in liver diseases, activities, electrophoretic profiles and immunolocalization of superoxide dismutase (SOD) in human liver specimens were investigated. Activities and electrophoresis were studied using liver homogenates in 41 cases and immunolocalization of Cu, Zn SOD was observed in 87 cases. Total SOD activity in acute viral hepatitis (AVH) and fatty liver (FL) groups was significantly lower than that in non-specific reactive hepatitis (NSRH) group. Cu, Zn SOD activity in AVH, FL and chronic active hepatitis (CAH) groups was also significantly lower than that in NSRH group. However, no difference of Mn SOD activity, was found between NSRH group and others. Decreased activity of superoxide dismutase in liver tissues suggests the release of this enzyme from the injured hepatocytes. In electrophoretic patterns of superoxide dismutase, 3 bands of Cu, Zn SOD isozymes and 8 to 10 bands of Mn SOD isozymes were recognized. Immunocytochemical investigation revealed the localization of Cu, Zn SOD in the cytoplasm of hepatocytes. Two different distribution of Cu, Zn SOD was observed in the lobules: a diffuse localization pattern and a focal one. The latter was found in the cases of liver diseases with severe parenchymal lesion. These findings suggest that superoxide radical anion and its scavenger, superoxide dismutase, may play an important role in the pathogenesis of liver cell necrosis.