Eskandari M K, Kalff J C, Billiar T R, Lee K K, Bauer A J
Division of Gastroenterology, Departments of Surgery and Medicine, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania 15261, USA.
Am J Physiol. 1999 Aug;277(2):G478-86. doi: 10.1152/ajpgi.1999.277.2.G478.
Cellular mechanisms of sepsis-induced ileus remain an enigma. The study aim was to determine the role of nitric oxide (NO) in mediating the suppression of rat jejunal circular smooth muscle activity during endotoxemia. Isolated muscularis inducible NO synthase (iNOS) mRNA was measured by RT-PCR, immunohistochemistry was employed to localize iNOS protein, and contractile activity was measured in an organ bath. The low basal expression of muscularis iNOS mRNA expression was increased in a time-dependent fashion after lipopolysaccharide (LPS), resulting in a 20-fold increase over controls 3 h after injection. Immunohistochemistry of muscularis whole mounts and dissociated muscularis cells for iNOS revealed staining only in the muscularis macrophages 12 h after LPS. LPS caused a 68% reduction in spontaneous muscle activity 12 h after injection, which improved by 53% after the in vitro application of the selective iNOS inhibitor L-N(6)-(1-iminoethyl)lysine. Similar results were obtained in C57BL/6 mice but not in iNOS knockout mice. These data demonstrate that macrophage iNOS plays an important role in mediating LPS-induced intestinal circular muscle suppression.
脓毒症诱导性肠梗阻的细胞机制仍是一个谜。本研究旨在确定一氧化氮（NO）在内毒素血症期间介导大鼠空肠环行平滑肌活动抑制中的作用。通过逆转录聚合酶链反应（RT-PCR）检测分离的肌层诱导型一氧化氮合酶（iNOS）mRNA，采用免疫组织化学法定位iNOS蛋白，并在器官浴中测量收缩活性。脂多糖（LPS）刺激后，肌层iNOS mRNA的基础低表达呈时间依赖性增加，注射后3小时比对照组增加了20倍。LPS注射12小时后，对肌层全层和分离的肌层细胞进行iNOS免疫组织化学检测，结果显示仅在肌层巨噬细胞中有染色。LPS注射12小时后使自发肌肉活动降低68%，在体外应用选择性iNOS抑制剂L-N(6)-(1-亚氨基乙基)赖氨酸后改善了53%。在C57BL/6小鼠中获得了类似结果，但在iNOS基因敲除小鼠中未获得。这些数据表明，巨噬细胞iNOS在介导LPS诱导的肠道环行肌抑制中起重要作用。
