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目的:观察失血性休克(HS)大鼠离体淋巴管对去甲肾上腺素(NE)反应性以及钙敏感性的变化,探讨淋巴管低反应性的钙敏机制。方法:Wistar雄性大鼠随机均分为sham组(仅手术)和HS组(复制HS模型,分为休克1 h、休克2 h亚组),制备胸导管环(每组均n=48)。采用离体淋巴管张力测定技术,观察淋巴管环对NE反应性以及钙敏性[梯度Ca2+与血管紧张素Ⅱ(AngⅡ)和胰岛素(Ins)分别孵育]变化。结果:与sham组相比,HS1 h组、HS 2 h组大鼠离体淋巴管对NE反应的量效曲线以及HS 2 h组淋巴管对Ca2+的量效曲线明显右移,对NE多个浓度的反应性以及不同Ca2+浓度的收缩力、最大收缩力(Emax)、亲和力指数(pD2)均显著降低。HS大鼠离体淋巴管环与钙敏感性增强剂AngⅡ孵育后,对NE的反应性以及钙敏感性均显著升高,但仍低于sham组;与钙敏感性抑制剂Ins孵育后,对NE的反应性以及钙敏感性均显著降低。结论:HS大鼠离体淋巴管的低反应性与钙失敏有关,这是休克时淋巴管收缩性降低的机制之一。
Objective: To observe the change of norepinephrine (NE) reactivity and calcium sensitivity in isolated lymphatic vessels of rats with hemorrhagic shock (HS) and to explore the mechanism of calcium responsiveness to lymphatic hyporesponsiveness. Methods: Male Wistar rats were randomly divided into sham group (operation only) and HS group (HS model was divided into shock 1 h, shock 2 h subgroup), thoracic duct rings were prepared (n = 48 in each group). In vitro lymphatic vessel tension measurement technique was used to observe the changes of NE reactivity and calcium sensitivity [Ca2 + and AngⅡ and Ins incubated separately] of lymphatic rings. Results: Compared with the sham group, the dose-response curve of lymphatic vessels in vitro and the dose-effect curve of lymphatic vessels of HS 2 h group in HS 2 h group and HS 2 h group were significantly shifted to the right of NE Concentration reactivity and contractility, maximal contractile force (Emax) and affinity index (pD2) of Ca2 + were significantly decreased. After reperfusion in vitro, the reactivity to calcium and the sensitivity to calcium in HS rats after the in vitro lymphatic rings were incubated with Ang II, but still lower than those in sham group. After incubation with calcium-sensitive inhibitor Ins NE reactivity and calcium sensitivity were significantly reduced. CONCLUSION: The low reactivity of isolated lymphatic vessels in HS rats is related to calcium desensitization, which is one of the mechanisms of reduced lymphatic contractility during shock.