Damage Induced by Oxygen Free Radicals in the Cell Fractionation of Regenerating Liver

Backgroud/Aims: Oxygen free radicals can be defined as oxygen molecules or molecular fragments that have an unpaired electron. They are formed in all living organisms during physiological and pathophysiological metabolism, and cause cell and tissue damages due to their high chemical reactivity. They can react with macromolecules including lipid, protein and DNA. Peroxidation of lipids exposed to oxygen free radicals is responsible for the damages of cells and tissues in vivo, which may cause cancer, inflammatory disease and liver disease. During the regeneration of the liver, there might be some alterations for metabolism of oxygen free radicals, which causes damage to regenerating liver. To know the degree of damage by oxygen free radicals in cell organelles of regenerating liver, hepatectomy was performed to the Sprgue-Dawley rats. Methods: From the regenerating liver obtained at day 3 after hepatectomy homogenate, mitochondria, microsome, cytosol, nuclei and plasma membrane were obtained as samples by sucrose linear density gradient centrifuger. Then, their malondialdehyde levels were measured by thiobarbituric acid assay. Results: The level of malondialdehyde level were increased in the homogenate, mitochondria, microsome and cytosol of the regenerating liver than in those of the original liver. Conclusions: These results suggest that mitochondria and microsome are susceptible to the oxygen free radicals in the regenerating liver.