Cytotoxicity of 7-ketocholesterol toward cultured rat hepatocytes and the effect of vitamin E.
The effects of 7-ketocholesterol on rat hepatocytes prepared by collagenase perfusion were examined. The viability of cells incubated with 100 microM 7-ketocholesterol was significantly lower than those with cholesterol, although the LDH activity in the cultured medium remained unchanged during the incubation. Hepatocytes treated with 7-ketocholesterol produced large amounts of .NO and O2- in the early stage of incubation. Treatment of the hepatocytes with Carboxy-PTIO, which selectively scavenged .NO, or with L-NMMA, an inhibitor of .NO synthase, increased the cell viability. The addition of 7-ketocholesterol to the culture medium tended to increase the ratio of total sterol to phospholipid of the hepatocytes in a time-dependent manner without changing the content of phospholipid. No lipid peroxidation or oxidation of the cellular SH groups, protein SH and glutathione, was apparent. Vitamin E added 1 h before the addition of 7-ketocholesterol prevented the hepatocytes from cell death by suppressing the incorporation of 7-ketocholesterol into the hepatocytes and by scavenging O2-.
Ohtani
K
K
Faculty of Human Life Science, Osaka City University, Japan.
Miyabara
K
K
Okamoto
E
E
Kamei
M
M
Matsui-Yuasa
I
I
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D016166:Free Radical Scavengers / Q000494:pharmacology; D007202:Indicators and Reagents; D007653:Ketocholesterols / Q000633:toxicity*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D010101:Oxygen Consumption / Q000187:drug effects; D010743:Phospholipids / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013261:Sterols / Q000378:metabolism; D014810:Vitamin E / Q000494:pharmacology*
D016166:Free Radical Scavengers; D007202:Indicators and Reagents; D007653:Ketocholesterols; D010743:Phospholipids; D013261:Sterols; D014810:Vitamin E; D009569:Nitric Oxide; D007770:L-Lactate Dehydrogenase; D019001:Nitric Oxide Synthase; C003001:7-ketocholesterol; D002118:Calcium