Protective effect of nitric oxide on hepatopulmonary syndrome from ischemia-reperfusion injury.
OBJECTIVE
To evaluate immunological protection of nitric oxide (NO) in hepatopulmonary syndrome and probable mechanisms of ischemia-reperfusion (IR) injury in rat liver transplantation.


METHODS
Sixty-six healthy male Wistar rats were randomly divided into three groups (11 donor/recipient pairs). In group II, organ preservation solution was lactated Ringer's solution with heparin 10, 000/μL at 4 °C. In groups I and III, the preservation solution added, respectively, L-arginine or N(G)-L-arginine methyl ester (L-NAME) (1 mmol/L) based on group II, and recipients were injected with L-arginine or L-NAME (50 mg/kg) in the anhepatic phase. Grafted livers in each group were stored for 6 h and implanted into recipients. Five rats were used for observation of postoperative survival in each group. The other six rats in each group were used to obtain tissue samples, and executed at 3 h and 24 h after transplantation. The levels of alanine aminotransferase (ALT), tumor necrosis factor (TNF)-α and NO metabolites (NOx) were detected, and expression of NO synthase, TNF-α and intercellular adhesion molecule 1 (ICAM-1) was examined by triphosphopyridine nucleotide diaphorase histochemical and immunohistochemical staining.


RESULTS
By supplementing L-arginine to strengthen the NO pathway, a high survival rate was achieved and hepatic function was improved. One-week survival rate of grafted liver recipients in group I was significantly increased (28.8 ± 36.6 d vs 4 ± 1.7 d, P < 0.01) as compared with groups II and III. Serum levels of ALT in group I were 2-7 times less than those in groups II and III (P < 0.01). The cyclic guanosine monophosphate (cGMP) levels in liver tissue and NOx in group I were 3-4 times higher than those of group II after 3 h and 24 h reperfusion, while in group III, they were significantly reduced as compared with those in group II (P < 0.01). The levels of TNF-α in group I were significantly lower than in group II after 3 h and 24 h reperfusion (P < 0.01), while being significantly higher in group III than group II (P < 0.01). Histopathology revealed more severe tissue damage in graft liver and lung tissues, and a more severe inflammatory response of the recipient after using NO synthase inhibitor, while the pathological damage to grafted liver and the recipient's lung tissues was significantly reduced in group I after 3 h and 24 h reperfusion. A small amount of constitutive NO synthase (cNOS) was expressed in liver endothelial cells after 6 h cold storage, but there was no expression of inducible NO synthase (iNOS). Expression of cNOS was particularly significant in vascular endothelial cells and liver cells at 3 h and 24 h after reperfusion in group II, but expression of iNOS and ICAM-1 was low in group I. There was diffuse strong expression of ICAM-1 and TNF-α in group III at 3 h after reperfusion.


CONCLUSIONS
The NO/cGMP pathway may be critical in successful organ transplantation, especially in treating hepatopulmonary syndrome during cold IR injury in rat orthotopic liver transplantation.
Department of Hepatobiliary Surgery and Liver Transplant Center, Jinan Military Region, The Chinese PLA 401st Hospital, Qingdao 266071, Shandong Province, China. diaotongjin@126.com
Tong-Jin
TJ
Diao
Xin
X
Chen
Li-Hua
LH
Deng
Han-Xiang
HX
Chen
Yan
Y
Liang
Xiao-Dong
XD
Zhao
Qing-Hua
QH
Wang
Wei-Sheng
WS
Yuan
Bai-Chun
BC
Gao
Yong
Y
Ye
D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D001120:Arginine / Q000008:administration & dosage / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000008:administration & dosage; D006530:Hepatorenal Syndrome / Q000209:etiology / Q000276:immunology / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D007150:Immunohistochemistry; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000276:immunology / Q000378:metabolism* / Q000473:pathology / Q000601:surgery*; D016031:Liver Transplantation / Q000009:adverse effects*; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000008:administration & dosage; D009569:Nitric Oxide / Q000097:blood / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000209:etiology / Q000276:immunology / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
D004791:Enzyme Inhibitors; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1; D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; D000410:Alanine Transaminase; D006152:Cyclic GMP; D019331:NG-Nitroarginine Methyl Ester