Susceptibility of cultured rat hepatocytes to oxidative stress by peroxides and iron. The extracellular matrix affects the toxicity of tert-butyl hydroperoxide.
The aim of this study was to set up an in vitro model for studying the importance of an altered extra-cellular matrix composition and its importance for the resistance to oxidative stress, in hepatocytes from normal and iron loaded rats. Primary cultures of hepatocytes from iron loaded and normal rats were plated on a laminin rich extracellular matrix or on collagen type I, and incubated with tert-butyl hydroperoxide (TBH). Malon dialdehyde (MDA) and the activities of lactate dehydrogenase (LDH) in cell culture medium were analyzed. The protein synthesis, the concentrations of glutathione and the expression of manganese-superoxide dismutase and ferritin genes were measured. All hepatocytes contained lower concentrations of glutathione when plated on collagen than on EHS. Ferritin H and Mn-SOD gene expression showed no difference. The rate of lipid peroxidation in iron loaded hepatocytes exposed to TBH was higher on collagen than in those plated on EHS (0.95 +/- 0.28 microM MDA vs. 1.62 +/- 0.22 microM MDA, p < 0.05). Iron loaded cells were in general more susceptible to TBH than were normal hepatocytes (MDA, LDH, protein synthesis and glutathione content). Lipid peroxidation could be prevented by adding desferrioxamine. In conclusion, we show that the combination of iron overload and collagen matrix in rat hepatocytes leads to an increased susceptibility to oxidative stress. These findings may be of interest for the further studies on effects of iron overload and the altered matrix composition in liver fibrosis.
Hagen
K
K
Department of Gastroenterology and Hepatology, Karolinska Hospital, Karolinska Institute, Stockholm, Sweden.
Zhu
C
C
Melefors
O
O
Hultcrantz
R
R
D000818:Animals; D015152:Blotting, Northern; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D003094:Collagen / Q000378:metabolism; D003676:Deferoxamine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005109:Extracellular Matrix / Q000502:physiology*; D005293:Ferritins / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008297:Male; D018384:Oxidative Stress / Q000502:physiology*; D010545:Peroxides / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000378:metabolism; D013997:Time Factors; D020122:tert-Butylhydroperoxide / Q000378:metabolism / Q000633:toxicity*
D002614:Chelating Agents; D010545:Peroxides; D003094:Collagen; D005293:Ferritins; D020122:tert-Butylhydroperoxide; D007501:Iron; D013482:Superoxide Dismutase; D005978:Glutathione; D003676:Deferoxamine