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目的观察内毒素休克大鼠血浆及主要脏器核因子(NF)κB活化规律及其对生物蝶呤(BH4)和一氧化氮(NO)表达水平的影响,探讨内毒素休克时NF-κB信号通路对BH4诱生NO的分子调控机制及其与多器官功能损害的关系。方法将47只大鼠按表格随机法分为正常组(8只)、内毒素／脂多糖(LPS)组(24只,每观察时相点8只,均同时注射LPS制成休克模型)和拮抗组[15只,每观察时相点5只,均同时注射LPS并以吡咯烷二硫代氨基甲酸盐(PDTC)拮抗]。休克及拮抗组于注射LPS后2、6、12 h观察,并与正常组同法处死,无菌留取大鼠血标本及肝、肺、肾组织,测定组织中NF-κB活性和三磷酸鸟苷环水解酶Ⅰ(GTP-CHⅠ)和诱导型一氧化氮合酶(iNOS)mRNA表达水平、血浆和组织中的BH4含量及NO水平、肝脏和肾脏功能指标、肺组织髓过氧化物酶活性。结果与正常组(例如肺组织中NF-κB活性为26±6)比较,LPS组大鼠组织中NF-κB迅速活化(P<0．01),并于注射后2 h达峰值(肺组织中为291±44);LPS组各组织中GTP-CHⅠ和iNOS mRNA表达、BH4和NO水平也较正常组明显升高(P<0．05或0．01),至伤后12 h仍持续较高水平。此外,该组相应器官功能均受到不同程度的损害。应用PDTC的拮抗组大鼠各组织中NF-κB活性均较LPS组有所降低,GTP-CHⅠ、iNOS mRNA表达及BH4、NO水平显著受抑,肝、肺、肾功能明显改善。结论内毒素休克时机体内NF-κB通路高度活化,并对BH4／NO系统具有明显调节效应;可通过下调BH4介导的iNOS的过度活化抑制NF-κB信号途径,从而减轻组织炎性反应,对机体脏器功能起到保护作用。
Objective To observe the activation of nuclear factor (NF) κB in plasma and major organs of endotoxic shock rats and its effect on the expression of biotin (BH4) and nitric oxide (NO) Molecular Mechanism of Pathway Regulating NO Produced by BH4 and Its Relationship with Multiple Organ Dysfunction. Methods Totally 47 rats were randomly divided into normal group (n = 8), LPS group (n = 24) Antagonism group [n = 15, each time point 5, both injected with LPS and antagonized with pyrrolidine dithiocarbamate (PDTC)]. The shock and antagonistic groups were observed at 2, 6, 12 h after LPS injection and sacrificed in the same way as the normal group. Blood samples of the rats and liver, lung and kidney were collected aseptically and the activities of NF-κB and triphosphate GTP-CHI and iNOS mRNA expression, plasma and tissue BH4 content and NO levels, liver and kidney function indicators, lung tissue myeloperoxidase active. Results Compared with normal group (for example, the NF-κB activity in lung tissue was 26 ± 6), NF-κB in LPS group was activated rapidly (P <0.01) and peaked at 2 h (291 ± 44). The expression of GTP-CHI and iNOS mRNA, the levels of BH4 and NO in LPS group were significantly higher than those in normal group (P <0.05 or 0.01), and remained at 12 h after injury Higher level. In addition, the corresponding organ function of the group suffered different degrees of damage. Compared with LPS group, NF-|ÊB activity of each group in PDTC antagonist group was decreased, GTP-CHI, iNOS mRNA expression and BH4, NO levels were significantly inhibited, liver, lung and kidney function improved significantly. Conclusion Endotoxin shock is highly activated in NF-κB pathway and has a significant regulatory effect on BH4 / NO system. It can inhibit the inflammatory response by down-regulating the activation of iNOS and inhibiting NF-κB signaling pathway. Body organs function to play a protective role.