Effect of Ca2+ channel blockers, external Ca2+ and phospholipase A2 inhibitors on t-butylhydroperoxide-induced lipid peroxidation and toxicity in rat liver slices.
OBJECTIVE
This study was undertaken to examine the effect of oxidant on lipid peroxidation and lethal cell injury in rat liver slices.


METHODS
t-Butylhydroperoxide (t-BHP) was employed as a model of an oxidant. The lipid peroxidation and lethal cell injury were estimated by measuring the formation of malondialdehyde (MDA) and lactate dehydrogenase (LDH) release, respectively.


RESULTS
t-BHP increased lipid peroxidation and LDH release in a dose-dependent manner over concentrations of 0.5-10 mM. t-BHP-induced lipid peroxidation was completely prevented by an antioxidant, N,N-diphenyl-p-phenylenediamine (DPPD), but LDH release was partially decreased. Both t-BHP-induced lipid peroxidation and LDH release were significantly protected by iron chelator, deferoxamine, sulfhydryl reducing agent, dithiothreitol and glutathione. Ca2+ channel blockers, verapamil, diltiazem and nifedipine exerted a significant protective effect against t-BHP-induced lipid peroxidation and LDH release. By contrast, addition of external Ca2+ chelator, ethylene glycol bis(b-aminoethyl ether)-N,N-tetraacetic acid (EGTA) did not alter t-BHP-induced lipid peroxidation, whereas t-BHP-induced lethal cell injury was significantly prevented. Phospholipase A2 (PLA2) inhibitors, mepacrine and butacaine produced a partial protective effect.


CONCLUSIONS
These results suggest that t-BHP induces cell injury by lipid peroxidation-dependent and -independent mechanisms which can be partially prevented by Ca2+ channel blockers and PLA2 inhibitors.
Heo
J
J
Department of Internal Medicine and Physiology, College of Medicine, Pusan National University, Korea.
Kim
G H
GH
Lee
K S
KS
Go
W U
WU
Ju
H J
HJ
Park
S K
SK
Song
C S
CS
Song
G A
GA
Cho
M
M
Yang
U S
US
Moon
H K
HK
Kim
Y K
YK
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D066298:In Vitro Techniques; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects*; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D010545:Peroxides / Q000633:toxicity; D010741:Phospholipases A / Q000037:antagonists & inhibitors*; D054467:Phospholipases A2; D051381:Rats; D017207:Rats, Sprague-Dawley; D020122:tert-Butylhydroperoxide
D002121:Calcium Channel Blockers; D004791:Enzyme Inhibitors; D010545:Peroxides; D020122:tert-Butylhydroperoxide; D007770:L-Lactate Dehydrogenase; D010741:Phospholipases A; D054467:Phospholipases A2; D002118:Calcium