Intestinal endotoxemia plays a central role in development of hepatopulmonary syndrome in a cirrhotic rat model induced by multiple pathogenic factors.
OBJECTIVE
To characterize the correlation between severity of hepatopulmonary syndrome (HPS) and degree of hepatic dysfunction, and to explore how intestinal endotoxemia (IETM) affects the development of HPS in cirrhotic rats.


METHODS
Male Wister rats were fed with a diet containing maize flour, lard, cholesterol, and alcohol and injected subcutaneously with CCl(4) oil solution every two days for 8 wk to induce typical cirrhosis and development of HPS. The animals were also given a nitric oxide (NO) production inhibitor, N(omega)-nitro-L-arginine methyl ester (L-NAME) intraperitoneally, and an iNOS inhibitor, aminoguanidine hydrochloride (AG) via gavage daily from the end of the 4th wk to the end of the 6th or 8th wk, or a HO-1 inhibitor, zinc protoporphyrin (ZnPP) intraperitoneally 12 h prior to killing. Blood, liver and lung tissues were sampled.


RESULTS
Histological deterioration of the lung paralleled to that of the liver in the cirrhotic rats. The number of pulmonary capillaries was progressively increased from 6.1 +/- 1.1 (count/filed) at the 4th wk to 14.5 +/- 2.4 (count/filed) at the 8th wk in the cirrhotic rats. Increased pulmonary capillaries were associated with increased blood levels of lipopolysaccharide (LPS) (0.31 +/- 0.08 EU/mL vs control 0.09 +/- 0.03 EU/mL), alanine transferase (ALT, 219.1 +/- 17.4 U/L vs control 5.9 +/- 2.2 U/L) and portal vein pressure. Compared with normal control animals, the number of total cells in bronchoalveolar lavage fluid (BALF) of the cirrhotic rats at the 8th wk was not changed, but the number of macrophages and the ratio of macrophages to total cells were increased by nearly 2-fold, protein expression of inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) started to increase significantly at the 4th wk, and reached its peak at the 8th wk in the lung of cirrhotic rats. The increase of iNOS expression appeared to be quicker than that of eNOS. NO(2)(-)/NO(3)(-) was also increased, which was correlated to the increase of iNOS (r = 0.7699, P < 0.0001) and eNOS (r = 0.5829, P < 0.002). mRNA expression of eNOS and iNOS was highly consistent with their protein expression.


CONCLUSIONS
Progression and severity of HPS as indicated by both increased pulmonary capillaries and histological changes are closely associated with LPS levels and progression of hepatic dysfunction as indicated by increased levels of ALT and portal vein pressure. Intestinal endotoxemia plays a central role in the development of HPS in the cirrhotic rat model by inducing NO and/or CO.
Zhang
Hui Ying
HY
Department of Pathophysiology, Changzhi Medical College, 161 Jie Fang Dong Jie, Changzhi 046000, Shanxi Province, China. zhhy2001@hotmail.com
Han
De Wu
DW
Su
Ai Rong
AR
Zhang
Li Tong
LT
Zhao
Zhong Fu
ZF
Ji
Jing Quan
JQ
Li
Bao Hong
BH
Ji
Cheng
C
D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D002196:Capillaries / Q000473:pathology; D002263:Carboxyhemoglobin / Q000378:metabolism; D016207:Cytokines / Q000097:blood; D018450:Disease Progression; D019446:Endotoxemia / Q000150:complications* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006146:Guanidines / Q000494:pharmacology; D006419:Heme Oxygenase (Decyclizing) / Q000037:antagonists & inhibitors / Q000378:metabolism; D020065:Hepatopulmonary Syndrome / Q000209:etiology* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D007410:Intestinal Diseases / Q000150:complications* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D008070:Lipopolysaccharides / Q000097:blood; D008099:Liver / Q000201:enzymology / Q000473:pathology* / Q000503:physiopathology; D008106:Liver Cirrhosis, Experimental / Q000150:complications* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D008168:Lung / Q000098:blood supply / Q000187:drug effects / Q000201:enzymology / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009389:Neovascularization, Pathologic / Q000209:etiology / Q000473:pathology; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III; D017082:Portal Pressure; D011524:Protoporphyrins / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012720:Severity of Illness Index; D013997:Time Factors; D015854:Up-Regulation
D016207:Cytokines; D004791:Enzyme Inhibitors; D006146:Guanidines; D008070:Lipopolysaccharides; D011524:Protoporphyrins; C017803:zinc protoporphyrin; D009569:Nitric Oxide; D008315:Malondialdehyde; D002263:Carboxyhemoglobin; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496318:Nos2 protein, rat; C496316:Nos3 protein, rat; D006419:Heme Oxygenase (Decyclizing); C491523:Hmox1 protein, rat; D000410:Alanine Transaminase; C004479:pimagedine; D019331:NG-Nitroarginine Methyl Ester