The role of nitric oxide after a short period of liver ischemia-reperfusion.
BACKGROUND
Liver ischemia-reperfusion injury is a serious problem during liver resection and transplantation. Nitric oxide (NO) has been suggested to have a cytoprotective effect for microcirculation, while the interaction of active oxygen species and NO produces peroxynitrite anion. The present study attempts to clarify the role of NO in liver ischemia-reperfusion injury.


METHODS
Wistar male rats were subjected to 30 min of hepatic ischemia followed by reperfusion. The model rats were divided into the three following groups: a control group that was not administered NO synthase inhibitors, and two experimental groups that were administered either N(omega)-nitro-L-arginine methyl ester (L-NAME) or aminoguanidine. In each group, we examined active oxygen species and nitric oxide production, and investigated liver function by measuring serum transaminase levels. In addition, we conducted histopathologic examinations and microcirculation examinations using intravital videomicroscopy.


RESULTS
In the control group, NO concentrations in the plasma increased with time after reperfusion. A decrease in NO production was detected in the groups administered NO synthase inhibitors. Elevated serum transaminase levels became more prominent after L-NAME administration, while aminoguanidine administration reduced its level. The degree of microcirculation failure was found to be more prominent in the L-NAME-administered group over both the control group and the aminoguanidine-administered group. A significantly lower survival rate was observed at 6 h after reperfusion in the L-NAME-administered group over that of the other groups.


CONCLUSIONS
A reduction of the ischemia-reperfusion injury is important in inhibiting the production of high-output NO and peroxynitrite, and in maintaining NO levels necessary for maintenance of microcirculation.
Morisue
Atsushi
A
Department of Surgery, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan.
Wakabayashi
Go
G
Shimazu
Motohide
M
Tanabe
Minoru
M
Mukai
Makio
M
Matsumoto
Kenji
K
Kawachi
Shigeyuki
S
Yoshida
Masashi
M
Yamamoto
Seiichiro
S
Kitajima
Masaki
M
D000818:Animals; D004791:Enzyme Inhibitors / Q000008:administration & dosage; D006146:Guanidines / Q000008:administration & dosage; D007263:Infusions, Parenteral; D008099:Liver / Q000098:blood supply* / Q000737:chemistry / Q000473:pathology; D008297:Male; D008833:Microcirculation; D023421:Models, Animal; D019331:NG-Nitroarginine Methyl Ester / Q000008:administration & dosage; D009569:Nitric Oxide / Q000096:biosynthesis / Q000097:blood / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000032:analysis / Q000037:antagonists & inhibitors; D052247:Nitric Oxide Synthase Type II; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000097:blood; D015427:Reperfusion Injury / Q000503:physiopathology* / Q000517:prevention & control; D013997:Time Factors; D000637:Transaminases / Q000097:blood; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000032:analysis
D004791:Enzyme Inhibitors; D006146:Guanidines; D017382:Reactive Oxygen Species; D009569:Nitric Oxide; C002744:3-nitrotyrosine; D014443:Tyrosine; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D000637:Transaminases; C004479:pimagedine; D019331:NG-Nitroarginine Methyl Ester