Effect of porto-systemic shunting on NOS expression after extended hepatectomy in rats.
OBJECTIVE
Several surgical procedures have been developed for reducing portal vein pressure to prevent postoperative liver injury. Nitric oxide synthase expression (NOS) induced by elevation of portal vein pressure is thought to play an important role in liver regeneration, but the details are not well understood.


METHODS
Rats in the control group and in the subcutaneous splenic transposition (SST) group underwent 90% partial hepatectomy. Survival and portal vein pressure were analyzed. The serum IL-6 and TNF-alpha levels were measured by enzyme-linked immunosorbent assay (ELISA). Hepatocyte proliferation and apoptosis 12 hours after hepatectomy were analyzed immunohistochemically. The protein and messenger RNA expression of inducible and endothelial NOS were analyzed using Western blotting and quantitative reverse transcriptase polymerase chain reaction, respectively.


RESULTS
The survival rate of the SST group was significantly higher. Portal vein pressure, TNF-alpha level and the apoptotic index were significantly lower in the SST group. Twelve hours after surgery, liver inducible NOS (iNOS) protein expression was significantly lower in the SST group. However, protein expression of endothelial NOS was not significantly different between the groups.


CONCLUSIONS
Inducible NOS expression after extended hepatectomy is related to the effects of porto-systemic shunting on the splanchnic circulation. Also, iNOS induction and concomitant nitric oxide generation appear to participate in the cytotoxicity of excessive portal pressure after extended hepatectomy.
Hayashi
Hironori
H
Department of Gastroenterologic Surgery, Division of Cancer Medicine, Graduate School of Medical Science, Kanazawa University, Ishikawa, Japan.
Shimizu
Koichi
K
Tani
Takashi
T
Takamura
Hiroyuki
H
Takeshita
Masaki
M
Nakamura
Keishi
K
Ninomiya
Itasu
I
Fushida
Sachio
S
Harada
Shin-Ichi
S
Kayahara
Masato
M