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Hepatic microvascular pressure during circulatory shock

循环休克期间的肝微血管压力

基本信息

批准号：
18591730
负责人：
SHIBAMOTO Toshishige
金额：
$ 2.31万
依托单位：
Kanazawa Medical University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

The main purpose of this study is to measure the hepatic microvascular pressure during circulatory shock in anesthetized rats. The transmural pressure (Pμhv) of the hepatic venule (the diameter 30-50μm) at the liver surface was measured, using a servonull micropipette pressure-measuring system. At first, we compared Pphv with the hepatic occlusion pressures determined with the hepatic vascular occlusion methods developed by the authors (Am. J. Physiol. 286:H121-H130, 2004) in isolated perfused rat livers during the basal states and hepatic venoconstriction induced by norepinephrine, increased blood flow and hepatic anaphylaxis. We found that Pphv is close to the double ooclusion pressure rather than the hepatic venous occlusion pressure. The second, we measured Pphv during anaphylactic hypotension in anesthetized rats. Anaphylactic hypotension was induced by an intravenous injection of 0.6 mg ovalbumin. When the antigen was injected, the systemic arterial pressure decreased profoundly … More to approximately 45 mmHg, which was accompanied by an increase in Ppv and Pphv: Pphv only transiently increased by 5.7 cmH_2O at lmin and then rapidly returned to the baseline within 2 min, when Ppv continued to increase and reached the peak of 36 cm H_2O at 3.5 min. This indicated that the constriction of the portal veins and the sinusoids much predominate over that of the hepatic veins. Along with this hepatic pre and sinusoidal constriction, the liver lobe thickness significantly decreased by 4% after antigen. Presinusoidal constriction during anaphylactic shock in anesthetized rats increased the portal venous pressure while the hepatic venular pressure only increased slightly and transiently. This predominant presinusoidal constriction is accompanied by a passive decrease in liver volume. Finally, we measured Pphv during endotoxin shock in anesthetized rats. Similar to anaphylactic hypotension, only transient and small increase in Pμhv was observed in response to an intravenous injection of E. coli endotoxin (10〜30mg/kg), indicating that the presinusoidal constriction was predominant during endotoxin shock in anesthetized rats. Less

本研究的主要目的是测量麻醉大鼠循环休克时肝脏微血管压力的变化。采用伺服微管压力测量系统测量肝表面肝小静脉（直径30 ~ 50μm）的跨壁压力（Pμhv）。首先，我们将Pphv与作者开发的肝血管闭塞方法测定的肝闭塞压力进行了比较。去甲肾上腺素引起的肝静脉收缩、血流量增加和肝过敏反应。我们发现Pphv更接近双闭压而不是肝静脉闭塞压。其次，我们测量了麻醉大鼠在过敏性低血压期间的Pphv。静脉注射卵清蛋白0.6 mg诱导过敏性低血压。注射抗原后，全身动脉压明显下降，降至45 mmHg左右，同时Ppv和Pphv升高，Pphv仅在1 min时短暂升高5.7 cmH_2O， 2 min后迅速恢复到基线水平，Ppv继续升高，在3.5 min时达到36 cmH_2O的峰值。这表明门静脉和窦状静脉的收缩比肝静脉的收缩更明显。随着肝前窦缩窄，抗原后肝叶厚度明显减少4%。麻醉大鼠过敏性休克时的窦前收缩使门静脉压升高，而肝静脉压仅轻微且短暂升高。主要的窦前收缩伴肝体积被动减小。最后，我们测量了内毒素休克时麻醉大鼠的Pphv。与过敏性低血压相似，静脉注射大肠杆菌内毒素（10 ~ 30mg/kg）后，Pμhv仅出现短暂性小幅升高，提示麻醉大鼠在内毒素休克时以窦前收缩为主。少