title: Effects of hyperbaric oxygen exposure on experimental hepatic ischemia reperfusion injury: relationship between its timing and neutrophil sequestration.
abstract: Recent studies have shown that hyperbaric oxygen therapy (HBOT) reduces neutrophil endothelial adherence in venules and also blocks the progressive arteriolar vasoconstriction associated with ischemia-reperfusion (I-R) injury in the extremities and the brain. In order to elucidate the effects of HBOT after I-R in digestive organs, particularly in the liver, we evaluated the following: 1) the relationship between timing of HBOT and tissue damage; and 2) HBOT's effects on neutrophil sequestration. Using a hepatic I-R (45 minute) model in male rats, survival rate, liver tissue damage, and neutrophil accumulation within the sinusoids in the HBOT-treated group (Group H) were compared to those in the nontreated group (Group C). For the HBOT-treated group, HBOT was administered as 100% oxygen, at 2.5 atm absolute, for 60 minutes. When HBOT was given 30 minute after I-R, the survival rate was much better in Group H than in Group C. HBOT performed within 3 hours of I-R markedly suppressed increases in the malondialdehyde level in tissues of the liver and lessened the congestion in the sinusoids. In addition, HBOT just after I-R caused decreased number of cells stained by the naphthol AS-D chloroacetate esterase infiltrating into the sinusoids. HBOT 3 hours after reperfusion, however, showed no clear effects upon neutrophil sequestration compared to Group C. These results indicate that HBOT performed within 3 hours of I-R alleviates hepatic dysfunction and improves the survival rate after I-R. Herein, we propose 1 possible mechanism for these beneficial effects: early HBOT given before neutrophil-mediated injury phase may suppress the accumulation of neutrophils after I-R. In conclusion, we believe that the present study should lead to an improved understanding of HBOT's potential role in hepatic surgery.
authors.affiliation: Department of Surgical Oncology and Digestive Surgery, Kagoshima University Graduate School of Medicine and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Kihara
authors.forename: Shinichi
authors.initials: S
authors.lastname: Ueno
authors.forename: Masahiko
authors.initials: M
authors.lastname: Sakoda
authors.forename: Takashi
authors.initials: T
authors.lastname: Aikou
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005500:Follow-Up Studies; D006931:Hyperbaric Oxygenation / Q000379:methods*; D008099:Liver / Q000098:blood supply* / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D018375:Neutrophil Activation / Q000502:physiology*; D009504:Neutrophils / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000473:pathology / Q000628:therapy*; D013997:Time Factors; D016896:Treatment Outcome