BACKGROUND/AIMS: Oxidative stress is presumed to play an important role in hepatic fibrogenesis. Diets high in polyunsaturated fatty acids (PUFA) enhance fibrosis and have been associated with increased oxidative damage in some models of liver injury. The aim of this study was to determine the effects of dietary fat of varying PUFA content on iron-induced oxidative stress and fibrosis. METHODS: Rats were given parenteral iron and diets supplemented with coconut oil, safflower oil or menhaden oil. RESULTS: Hepatic iron overload was associated with induction of heme oxygenase-1, a sensitive indicator of oxidative stress, and with modest increases in hydroxyproline and procollagen I mRNA levels without histologically evident fibrosis, all of which were unaffected by dietary fat. In addition, iron loading was associated with increases in cysteine, gamma-glutamylcysteine and glutathione. Dietary fat brought about the expected alterations in peroxidizability, but did not alter indices of oxidative damage. CONCLUSION: These data highlight the distinction between oxidative stress and oxidative damage and suggest that the former is not sufficient to elicit overt fibrosis. Furthermore, while hepatic iron overload leads to oxidative stress, there is an associated upregulation of antioxidant defenses involving thiol metabolism that may be a critical factor limiting the accumulation of oxidative damage.
BACKGROUND/AIMS: Oxidative stress is presumed to play an important role in hepatic fibrogenesis. Diets high in polyunsaturated fatty acids (PUFA) enhance fibrosis and have been associated with increased oxidative damage in some models of liver injury. The aim of this study was to determine the effects of dietary fat of varying PUFA content on iron-induced oxidative stress and fibrosis. METHODS:Rats were given parenteral iron and diets supplemented with coconut oil, safflower oil or menhaden oil. RESULTS: Hepatic iron overload was associated with induction of heme oxygenase-1, a sensitive indicator of oxidative stress, and with modest increases in hydroxyproline and procollagen I mRNA levels without histologically evident fibrosis, all of which were unaffected by dietary fat. In addition, iron loading was associated with increases in cysteine, gamma-glutamylcysteine and glutathione. Dietary fat brought about the expected alterations in peroxidizability, but did not alter indices of oxidative damage. CONCLUSION: These data highlight the distinction between oxidative stress and oxidative damage and suggest that the former is not sufficient to elicit overt fibrosis. Furthermore, while hepatic iron overload leads to oxidative stress, there is an associated upregulation of antioxidant defenses involving thiol metabolism that may be a critical factor limiting the accumulation of oxidative damage.
Authors: José María Moreno-Navarrete; Francisco Ortega; Amaia Rodríguez; Jèssica Latorre; Sara Becerril; Mònica Sabater-Masdeu; Wifredo Ricart; Gema Frühbeck; José Manuel Fernández-Real Journal: Diabetologia Date: 2017-02-27 Impact factor: 10.122
Authors: Kyle E Brown; M Meleah Mathahs; Kimberly A Broadhurst; Mitchell C Coleman; Lisa A Ridnour; Warren N Schmidt; Douglas R Spitz Journal: Free Radic Biol Med Date: 2006-10-17 Impact factor: 7.376
Authors: Jianling Wang; Huaxian Ma; Paul J Boor; V M Sadagopa Ramanujam; G A S Ansari; M Firoze Khan Journal: Free Radic Biol Med Date: 2009-12-04 Impact factor: 7.376
Authors: George A Asare; Michael C Kew; Kensese S Mossanda; Alan C Paterson; Kwanele Siziba; Christiana P Kahler-Venter Journal: J Clin Biochem Nutr Date: 2008-12-27 Impact factor: 3.114