Meyer T A, Tiao G M, James J H, Noguchi Y, Ogle C K, Fischer J E, Hasselgren P O
Department of Surgery, University of Cincinnati Medical Center, Ohio, USA.
J Surg Res. 1995 Jun;58(6):570-5. doi: 10.1006/jsre.1995.1090.
In recent studies, production of interleukin-6 (IL-6) in cultured enterocytes was stimulated by lipolysaccharide (LPS). In other cell types, IL-6 production was inhibited by nitric oxide (NO). We tested the hypothesis that LPS-induced IL-6 production in the enterocyte is regulated, at least in part, by NO. IEC-6 cells (a rat intestinal epithelial cell line) were cultured for 3 days with different combinations of LPS (1-10 micrograms/ml), the NO synthase inhibitor N-omega-nitro-L-arginine (NNA, 3-300 microM), L-arginine (10 mM), the NO donor sodium nitroprusside (SNP, 0.5-1 microM), or medium alone as control. IL-6 levels in the culture medium were determined by the B9 murine hybridoma bioassay. Nitrite, a stable end product of NO metabolism, was measured by HPLC. PCR was performed to determine inducible NO synthase (iNOS) mRNA expression in the IEC-6 cells. Treatment of IEC-6 cells with LPS stimulated IL-6 production. LPS-induced IL-6 production was further increased by NNA in a dose-dependent fashion. This effect of NNA was abolished by the addition of L-arginine. SNP caused a dose-dependent decrease in IL-6 production. Nitrite production was increased in a dose-dependent fashion after LPS treatment. PCR revealed an increase in iNOS mRNA expression in IEC-6 cells after administration of 1 microgram/ml LPS. The results suggest that NO inhibits LPS-induced IL-6 production in the enterocyte. NO may be an important regulator of intestinal cytokine response during sepsis and endotoxemia.
在最近的研究中，脂多糖（LPS）刺激培养的肠上皮细胞产生白细胞介素-6（IL-6）。在其他细胞类型中，一氧化氮（NO）抑制IL-6的产生。我们检验了这样一个假设，即肠上皮细胞中LPS诱导的IL-6产生至少部分受NO调节。将IEC-6细胞（一种大鼠肠道上皮细胞系）用LPS（1 - 10微克/毫升）、一氧化氮合酶抑制剂N-ω-硝基-L-精氨酸（NNA，3 - 300微摩尔）、L-精氨酸（10毫摩尔）、NO供体硝普钠（SNP，0.5 - 1微摩尔）的不同组合或单独的培养基作为对照培养3天。通过B9小鼠杂交瘤生物测定法测定培养基中的IL-6水平。通过高效液相色谱法测定NO代谢的稳定终产物亚硝酸盐。进行聚合酶链反应（PCR）以确定IEC-6细胞中诱导型一氧化氮合酶（iNOS）mRNA的表达。用LPS处理IEC-6细胞刺激了IL-6的产生。NNA以剂量依赖的方式进一步增加了LPS诱导的IL-6产生。添加L-精氨酸消除了NNA的这种作用。SNP导致IL-6产生呈剂量依赖性减少。LPS处理后亚硝酸盐产生呈剂量依赖性增加。PCR显示给予1微克/毫升LPS后IEC-6细胞中iNOS mRNA表达增加。结果表明NO抑制肠上皮细胞中LPS诱导的IL-6产生。NO可能是脓毒症和内毒素血症期间肠道细胞因子反应的重要调节因子。
