SUPEROXIDE DISMUTASE ACTIVITY IN LIVER CELLS OF RATS UNDER CONDITIONS OF TOXIC DOSES OF ACETAMINOPHEN ADMINISTRATION AND PARTIAL HEPATECTOMY

The aim of this work was to investigate the activities of Mn- and Cu,Zn-dependent superoxide dismutase in the mitochondrial and cytosolic fractions of liver cells in rats under conditions of toxic doses of acetaminophen administration and partial hepatectomy. Partial hepatectomy (a surgical procedure for the removal of two-thirds of the liver mass), used to study liver regeneration processes under laboratory conditions, was performed following the method of Mitchell and Willenbring (2008) exclusively under sterile conditions to minimize the risk of infections. The mitochondrial and cytosolic fractions of rat liver cells were obtained using the method of differential preparative centrifugation. The activity of Mn- and Cu,Zn-dependent superoxide dismutase in the mitochondrial and cytosolic fractions of the liver was assessed based on the ability of superoxide dismutase to inhibit adrenaline autooxidation. It was established that in the liver of control rats after partial hepatectomy, activation of Mn- and Cu,Zn-dependent superoxide dismutase occurs only during the early stages (24 h and 48 h) of the regeneration process, likely aimed at increasing the level of superoxide anion radicals. In animals with toxic injury, the course of reparative regeneration is characterized by a decrease in Mn-superoxide dismutase activity in mitochondria against the background of Cu,Zn-SOD activation in the cytosol throughout the entire experimental period, which is likely reflects the implementation of compensatory antioxidant defense mechanisms of hepatocytes in response to their depletion in mitochondria. Keywords: Cu,Zn-superoxide dismutase, Mn-superoxide dismutase, mitochondria, liver, acetaminophen, partial hepatectomy, regeneration