Mesenteric nitric oxide and superoxide production in experimental necrotizing enterocolitis.
Mesenteric nitric oxide and superoxide production in experimental necrotizing enterocolitis.
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实验性坏死性小肠结肠炎中肠系膜一氧化氮和超氧化物的产生。
DOI：
10.1016/j.jss.2009.07.028
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Gourlay,DavidM
中科院分区：
文献类型：
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作者：
Whitehouse,JillS;Xu,Hao;Shi,Yang;Noll,LeAnne;Kaul,Sushma;Jones,DeronW;PritchardJr,KirkwoodA;Oldham,KeithT;Gourlay,DavidM
GROUNDA提出坏死性小肠结肠炎（NEC）的肠损伤机制涉及通过改变一氧化氮合酶（NOS）活性引起的血管功能障碍。我们假设，这种功能障碍的结果在一氧化氮（·NO）和超氧化物（O2·-）的生产不平衡的肠血管内皮细胞，这有助于肠损伤看到NEC.MATERIALS和METHODS新生大鼠幼崽被分为两组。对照组幼仔母乳喂养，并与其母亲一起饲养。将实验NEC幼仔单独圈养，并暴露于配方饲料和单独的5%至10%缺氧（FF/H）或添加脂多糖（FF/H/LPS）。用NG-单甲基-L-精氨酸（L-NMMA）抑制NOS，分析各组肠系膜的·NO和O2·-产生。进行eNOS、磷酸化eNOS（phospho-eNOS）和诱导型NOS（iNOS）的蛋白质印迹分析，并通过组织学对每个末端回肠的肠损伤进行分级。病理组织学显示FF/H组中轻度肠损伤（4分制1-2级），FF/H/LPS组中重度损伤（3-4级）。FF/H组显著增加·NO和降低O2·-产生，而FF/H/LPS组转变为显著降低·NO和增加O2·-产生。L-NMMA在所有三组中抑制了>50%的O2·-产生，但仅抑制对照组和FF/H幼崽中的·NO产生。Western blot分析显示FF/H幼鼠中磷酸化eNOS水平增加，FF/H/LPS幼鼠中iNOS水平增加。结论：本研究表明，在NEC的进展中，肠缺血与NO向O2-产生的转变有关，这是NOS依赖性的。血管舒张功能受损和活性氧的过度产生可能导致更大的损伤。
BACKGROUNDA proposed mechanism of intestinal injury in necrotizing enterocolitis (NEC) involves vascular dysfunction through altered nitric oxide synthase (NOS) activity. We hypothesize that this dysfunction results in an imbalance in nitric oxide (•NO) and superoxide (O2•–) production by the intestinal vascular endothelium, which contributes to the intestinal injury seen in NEC.MATERIALS AND METHODSNeonatal rat pups were divided into two groups. Control pups were breast fed and housed with their mother. Experimental NEC pups were housed separately and either exposed to formula feeding and 5% to 10% hypoxia alone (FF/H) or with the addition of lipopolysaccharide (FF/H/LPS). Mesenteries from each group were analyzed for •NO and O2•–production with and without NOS inhibition by NG-monomethyl-L-arginine (L-NMMA). Western blot analysis for eNOS, phosphorylated eNOS (phospho-eNOS), and inducible NOS (iNOS) was performed, and each terminal ileum was graded for intestinal injury by histology.RESULTSHistology revealed mild intestinal injury (grade 1–2 on a 4-point scale) in the FF/H group and severe injury (grade 3–4) in the FF/H/LPS group. The FF/H cohort had significantly increased •NO and lower O2•–production, while the FF/H/LPS group shifted to significantly decreased •NO and increased O2•–production. L-NMMA inhibited >50% of O2•–production in all three groups but only inhibited •NO production in control and FF/H pups. Western blot analysis revealed increased levels of phospho-eNOS in FF/H pups and increased iNOS in FF/H/LPS pups.CONCLUSIONSThis study demonstrates in the progression of NEC, intestinal ischemia is associated with a shift from •NO to O2•–production, which is NOS-dependent. Potentially greater injury results from impaired vasodilatation and over-production of reactive oxygen species.