title: Arterial hypoxemia and intrapulmonary vasodilatation in rat models of portal hypertension.
abstract: BACKGROUND
  Rats with chronic bile duct ligation (CBDL) and portal vein ligation (PVL) are used as models of portal hypertension. CBDL rats show hypoxemia with intrapulmonary vasodilatation (IPVD), and are recognized as a model of hepatopulmonary syndrome (HPS), while PVL rats are normoxemic. We investigated the differences in arterial oxygenation between these models, and the key factors leading to HPS.
  
  
  METHODS
  Forty-eight Sprague-Dawley rats were prepared as CBDL or PVL models, or as Sham rats. Arterial oxygenation, hemodynamics (reference sample method), and IPVD were simultaneously evaluated in conscious and unrestrained animals, using (141)Ce- or (113)Sn-labeled microspheres (15 microm in diameter), respectively. Endothelin-1 (ET-1) and nitrate/nitrite (end products of nitric oxide; NOx) production by the lung tissue (increment across the lungs) was also determined.
  
  
  RESULTS
  The extent of IPVD was similar in both models, but hypoxemia was only observed in CBDL rats. The ET-1 level and the increment in NOx were significantly increased in CBDL rats, and the increment was directly correlated with impairment of oxygenation. Blood flow through the bronchial arteries (anatomical shunting) was increased in CBDL rats, reaching more than three times the level in PVL rats or Sham rats.
  
  
  CONCLUSIONS
  These results support the hypothesis that NO derived from the lung tissues contributes to hypoxemia, and IPVD appears to be a prerequisite for impaired oxygenation. The considerable increase of anatomical shunting may potentially contribute to impaired oxygenation in CBDL rats.
authors.affiliation: First Department of Internal Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, 113-8603, Japan.
authors.forename: Yasumi
authors.initials: Y
authors.lastname: Katsuta
authors.forename: Xue-Jun
authors.initials: XJ
authors.lastname: Zhang
authors.forename: Masaru
authors.initials: M
authors.lastname: Ohsuga
authors.forename: Toshio
authors.initials: T
authors.lastname: Akimoto
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Komeichi
authors.forename: Shuji
authors.initials: S
authors.lastname: Shimizu
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Kato
authors.forename: Akiko
authors.initials: A
authors.lastname: Miyamoto
authors.forename: Katsuaki
authors.initials: K
authors.lastname: Satomura
authors.forename: Teruo
authors.initials: T
authors.lastname: Takano
mesh_terms: D000818:Animals; D001158:Arteries; D004195:Disease Models, Animal; D019332:Endothelin-1 / Q000096:biosynthesis; D020065:Hepatopulmonary Syndrome / Q000503:physiopathology*; D006975:Hypertension, Portal / Q000503:physiopathology*; D000860:Hypoxia / Q000209:etiology*; D008168:Lung / Q000098:blood supply*; D008297:Male; D008863:Microspheres; D009566:Nitrates / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D010100:Oxygen / Q000097:blood*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014664:Vasodilation / Q000502:physiology*
chemical_list: D019332:Endothelin-1; D009566:Nitrates; D009573:Nitrites; D010100:Oxygen