• Tomonobu Koizumi, Hitoshi Ogasawara, Hiroshi Yamamato, Kenji Tsushima, Zonghai Ruan, Mingyuan Jian, Keisaku Fujimoto, and Keishi Kubo.
• First Department of Medicine, Shinshu University School of Medicine, Asahi Matsumoto, Japan. tomonobu@hsp.md.shinshu-u.ac.jp
• Anesthesiology. 2004 Jul 1; 101 (1): 59-65.

BackgroundThe effect of nitric oxide synthase inhibitor on acute lung injury remains controversial. The current study was designed to examine effects of a newly synthesized and selective inducible nitric oxide synthase inhibitor, ONO1714, on endotoxin-induced lung injury in unanesthetized sheep.MethodsThirteen unanesthetized sheep chronically instrumented with a lung lymph fistula and vascular catheters for monitoring were prepared. Animals were randomly allocated into two experimental groups. In experiment 1, sheep (n = 6) were infused only with endotoxin (1 microg/kg) for 30 min. In experiment 2, sheep (n = 7) were pretreated with ONO1714 (0.1 mg/kg) before 30 min of endotoxin administration, and the endotoxin was infused in the same manner as in experiment 1. Mean pulmonary arterial pressure, left atrial pressure, systemic arterial pressure, and lung lymph flow were measured. Observation was continued over 5 h after endotoxin administration.ResultsONO1714 did not cause any pulmonary hemodynamic changes at baseline or exert any influences on transient pulmonary hypertension and increased pulmonary vascular resistance during endotoxemia. However, inducible nitric oxide synthase inhibition with ONO1714 significantly reduced lung lymph filtration and improved abnormal oxygenation during endotoxemia. In addition, increased nitrate-nitrite in plasma and lung lymph in response to endotoxin was prevented by treatment with ONO1714.ConclusionsThese findings suggest that nitric oxide release by the inducible nitric oxide synthase pathway partially contributes to the increased permeability of pulmonary edema and decreased oxygenation during endotoxemia in sheep.

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