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Effect of inducible nitric oxide synthase on intestinal microcirculation in endotoxic shock

Shi Enwei, Jiang Xiaojing, Bai Han, Gu Tianxiang, Nakajima Yoshiki

Department of Cardiac Surgery, the First Affiliated Hospital, China Medical University.Shenyang 110001,Liaoning；China；Department of Infectious Disease,the Second Affiliated Hospital, China Medical University.Shenyang 110004,Liaoning

Abstract

To investigate the changes of intestinal microcirculation in endotoxic shock and the effect of inducible nitric oxide synthase (iNOS) on intestinal microcirculation, endotoxic shock was induced by intravenous injection of lipopolysaccharide (LPS) in mice. Mean arterial pressure (MAP) was monitored throughout the experimental procedure. The velocity and flux of red blood cell (RBC) in villus tip arteriole and capillaries were measured by FITC-labeled erythrocytes and intravital microscopy. The effect of iNOS was determined by targeted disruption of mice iNOS-gene and administration of S-methylthiourea sulfate (SMT), a selective inhibitor of iNOS, before LPS injection. No significant differences in MAP, RBC velocity and flux at baseline were found among wild type mice, SMT pretreated mice and iNOS-gene knockout mice. LPS induced a dramatic fall of MAP in wild type mice. The decrease of MAP was significantly restored in iNOS-gene knockout mice and in wild type mice received SMT before LPS injection. The velocity and flux of RBC in villus tip arteriole and capillaries decreased markedly after LPS injection in wild type mice, while significantly higher velocity and flux of RBC were found in iNOS-gene knockout mice and SMT-pretreated mice both 60 and 120 minutes after LPS injection. The results demonstrate that iNOS plays an essential role in the intestinal microcirculation disturbance which occurs in endotoxic shock.

Key words: Nitric oxide synthase;Endotoxic shock;Microcirculation

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Citing This Article：

Shi Enwei, Jiang Xiaojing, Bai Han, Gu Tianxiang, Nakajima Yoshiki. Effect of inducible nitric oxide synthase on intestinal microcirculation in endotoxic shock . Acta Physiol Sin 2005; 57 (1): (in Chinese with English abstract).