Effects of Controlled Mechanical Ventilation on Sepsis-Induced Diaphragm Dysfunction in Rats
Effects of Controlled Mechanical Ventilation on Sepsis-Induced Diaphragm Dysfunction in Rats
复制标题
DOI：
10.1097/ccm.0000000000000685
复制
发表时间：
2014-12-01
影响因子：
8.8
通讯作者：
Gayan-Ramirez, Ghislaine
中科院分区：
文献类型：
--
作者：
Maes, Karen;Stamiris, Angela;Gayan-Ramirez, Ghislaine
目的：严重脓毒症时，由于血流动力学、代谢和固有的异常，会发生横隔膜功能障碍。同样，12小时的受控机械通气也会促进横隔膜功能障碍。重要的是，脓毒症患者通常要接受几天的机械通气治疗。目前尚不清楚控制性机械通气是否会加重脓毒症所致的横隔膜功能障碍，这构成了这些实验的基础。我们研究了12小时可控机械通气对脓毒症大鼠膈肌收缩功能、纤维大小、细胞因子产生、蛋白分解、自噬和氧化应激的影响。设计：随机对照实验。地点：动物研究实验室。受试者：成年雄性Wistar大鼠。干预：一次性腹腔注射生理盐水或大肠杆菌脂多糖(5 mg/kg)。12h后，生理盐水处理动物(控制性机械通气)和一半脓毒症动物(脂多糖+控制性机械通气)接受12h的控制性机械通气，其余的脓毒症动物(脂多糖组)自主呼吸12h。他们被与对照组进行比较。所有动物在注射生理盐水或脂多糖24小时后进行实验研究。测量和主要结果：注射生理盐水或脂多糖24小时后，在体外测定膈肌收缩力。我们还从染色的横断面上测量了横隔肌纤维的大小，并通过蛋白质组阵列测定了炎性细胞因子。用免疫印迹和定量聚合酶链式反应检测钙蛋白酶、半胱氨酸天冬氨酸氨基转移酶-3和蛋白酶体的活性、20S-蛋白酶体α亚基的表达、E_2结合物、E_3连接酶和自噬。脂多糖和/或控制的机械通气量独立地降低了横隔膜的收缩能力和纤维尺寸，增加了横隔膜IL-6的产生、蛋白质的泛素化、Atrogin-1和Murf-1的表达、钙蛋白酶和caspase-3的活性、自噬和蛋白质氧化。与单纯脂多糖相比，内毒素+机械通气可加重脓毒症大鼠横隔膜收缩功能障碍，增加横隔膜白介素6水平、自噬和蛋白质氧化水平，但对横隔膜纤维大小、钙蛋白、caspase-3和蛋白酶体激活无明显影响。结论：12h可控机械通气加重了脓毒症所致的横隔肌功能障碍，可能与促炎细胞因子产生增加、自噬和氧化应激加重有关。
Objectives: Diaphragm dysfunction develops during severe sepsis as a consequence of hemodynamic, metabolic, and intrinsic abnormalities. Similarly, 12 hours of controlled mechanical ventilation also promotes diaphragm dysfunction. Importantly, patients with sepsis are often treated with mechanical ventilation for several days. It is unknown if controlled mechanical ventilation exacerbates sepsis-induced diaphragm dysfunction, and this forms the basis for these experiments. We investigate the effects of 12-hour controlled mechanical ventilation on contractile function, fiber dimension, cytokine production, proteolysis, autophagy, and oxidative stress in the diaphragm of septic rats.Design: Randomized controlled experiment.Setting: Animal research laboratory.Subjects: Adult male Wistar rats.Interventions: Treatment with a single intraperitoneal injection of either saline or Escherichia coli lipopolysaccharide (5 mg/kg). After 12 hours, the saline-treated animals (controlled mechanical ventilation) and half of the septic animals (lipopolysaccharide + controlled mechanical ventilation) were submitted to 12 hours of controlled mechanical ventilation while the remaining septic animals (lipopolysaccharide) were breathing spontaneously for 12 hours. They were compared to a control group. All animals were studied 24 hours after saline or lipopolysaccharide administration.Measurements and Main Results: Twenty-four hours after saline or lipopolysaccharide administration, diaphragm contractility was measured in vitro. We also measured diaphragm muscle fiber dimensions from stained cross sections, and inflammatory cytokines were determined by proteome array. Activities of calpain, caspase-3, and proteasome, expression of 20S-proteasome alpha subunits, E2 conjugases, E3 ligases, and autophagy were measured with immunoblotting and quantitative polymerase chain reaction. Lipopolysaccharide and/or controlled mechanical ventilation independently decreased diaphragm contractility and fiber dimensions and increased diaphragm interleukin-6 production, protein ubiquitination, expression of Atrogin-1 and Murf-1, calpain and caspase-3 activities, autophagy, and protein oxidation. Compared with lipopolysaccharide alone, lipopolysaccharide + controlled mechanical ventilation worsened diaphragm contractile dysfunction, augmented diaphragm interleukin-6 levels, autophagy, and protein oxidation, but exerted no exacerbating effects on diaphragm fiber dimensions, calpain, caspase-3, or proteasome activation.Conclusions: Twelve hours of controlled mechanical ventilation potentiates sepsis-induced diaphragm dysfunction, possibly due to increased proinflammatory cytokine production and autophagy and worsening of oxidative stress.