Department of Intensive Care Unit, Zhongnan Hospital of Wuhan University, Wuhan, Hubei Province, China.
Shock. 2013 Aug;40(2):144-51. doi: 10.1097/SHK.0b013e318299e9c0.
We tested the effect of vagus nerve stimulation in endotoxin-induced intestinal tight junction injury in mice challenged with lipopolysaccharide (LPS) and examined the role of α7 nicotinic acetylcholine receptors (α7nAchR) in this process. Endotoxemia was induced by intraperitoneal injection of LPS (10 mg/kg) in male Balb/c mice. Samples were collected 12 h after LPS treatment. Endotoxemia was associated with intestinal barrier dysfunction, as evidenced by increased amount of fluorescein isothiocyanate-dextran in circulation. Western blot and immunofluorescence was performed, and the results demonstrated decreased expression of occludin and zonula occludens 1 along intestinal epithelium in endotoxemic mice. The ultrastructure of tight junction was disrupted as shown by transmission electron microscopy, which was associated with increased intestinal permeability. Stimulation of the right cervical vagus nerve ameliorated the damage of tight junction ultrastructure, which was consistent with decreased permeability to fluorescein isothiocyanate-dextran, and also reversed the decreased expression of tight junction proteins occludin and zonula occludens 1. Vagus nerve stimulation inhibited the upregulated activity of myosin light chain kinase and nuclear factor κB. In contrast, α-bungarotoxin (a specific α7nAchR antagonist, 0.1 μg/mouse) administered before vagus nerve stimulation significantly abolished these protective effects of vagus nerve stimulation. Our results for the first time confirmed that vagus nerve stimulation attenuated the disruption of tight junction in intestinal epithelium in endotoxemic mice, which was mediated through suppressing translocation of nuclear factor κB p65, downregulating myosin light chain kinase, and the α7nAchR may play an important role in this process.
我们测试了迷走神经刺激对内毒素诱导的小鼠肠紧密连接损伤的影响,并研究了α7 烟碱型乙酰胆碱受体(α7nAchR)在这一过程中的作用。内毒素血症通过腹腔注射脂多糖(LPS,10mg/kg)在雄性 Balb/c 小鼠中诱导。在 LPS 处理后 12 小时收集样本。内毒素血症与肠道屏障功能障碍有关,这表现在循环中荧光素异硫氰酸酯-葡聚糖的量增加。进行了 Western blot 和免疫荧光分析,结果表明内毒素血症小鼠肠上皮中闭合蛋白和紧密连接蛋白 1 的表达减少。透射电子显微镜显示紧密连接的超微结构被破坏,这与肠道通透性增加有关。右侧颈迷走神经刺激改善了紧密连接超微结构的损伤,这与荧光素异硫氰酸酯-葡聚糖的通透性降低有关,也逆转了紧密连接蛋白闭合蛋白和紧密连接蛋白 1 的表达减少。迷走神经刺激抑制肌球蛋白轻链激酶和核因子 κB 的上调活性。相比之下,预先给予α-银环蛇毒素(一种特异性的 α7nAchR 拮抗剂,0.1μg/只)显著消除了迷走神经刺激的这些保护作用。我们的研究结果首次证实,迷走神经刺激减轻了内毒素血症小鼠肠上皮紧密连接的破坏,这是通过抑制核因子 κB p65 的易位、下调肌球蛋白轻链激酶来实现的,α7nAchR 可能在这一过程中发挥重要作用。