脂多糖诱导脓毒症大鼠脑内氧化损伤及相关信号通路的研究

摘要

Objective To investigate the mechanism of oxidative damage caused by lipopolysaccharide (LPS)induced sepsis in rat brain.Methods The rats were randomly divided into control group and model group (low LPS group and high LPS group).Twenty-four hours after the modeling,the rats were sacrificed before their brain tissue was taken out and prepared for the test.The changes in malondialdehyde (MDA),superoxide dismutase (SOD),glutathione peroxidase (GSH-Px),total antioxidant capacity (T-AOC),hydrogen peroxide (H2 O2 )and succinate dehydrogenase (SDH)were detected.The expression level of JNK and Nrf2 protein in brain tissue was detected by qRT-PCR and Western blotting. Results Compared with the control group,the MDA,SOD,GSH-px,T-AOC,H2O2 and SDH level increased significantly in the model group,and the difference in expressions of JNK and Nrf2 was statistically significant (P <0.05). Conclusion The LPS induced septic oxidative brain damage model in rats is successfully established,and the process may be regulated through the Nrf2 and JNK signal pathways.%目的：探讨脂多糖（lipopolysaccharide，LPS）诱导的脓毒症造成大鼠脑内氧化损伤的作用及 JNK、Nrf2相关信号的变化。方法将大鼠随机分为对照组、低剂量模型组（LPS 5 mg／kg）和高剂量模型组（LPS 10 mg／kg）。模型组造模24 h 后，活杀大鼠，将脑组织完全取出后，剪碎并研磨成脑匀浆，检测丙二醛（MDA）、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）、总抗氧化能力（T-AOC）、过氧化氢（H2 O2）、琥珀酸脱氢酶（SDH）的变化。利用 qRT-PCR、Western 印迹检测 JNK 与 Nrf2蛋白在脑组织亚细胞中的表达水平。结果与对照组比较，在 LPS诱导脓毒症大鼠模型中，模型组大鼠脑组织中，MDA、H2 O2、SDH 含量增加，SOD、GSH-Px、T-AOC 含量减少，JNK mRNA水平与总蛋白水平未受明显影响（P ＞0．05），但磷酸化水平（p-JNK）显著升高（P ＜0．01）；Nrf2 mRNA 水平与总蛋白水平显著上调（P ＜0．01），且磷酸化水平（p-Nrf2）也显著升高（P ＜0．01），差异具有统计学意义。结论成功构建 LPS 诱导脓毒血症后大鼠脑内氧化损伤的病理模型，并发现在这一病理过程中 p-JNK、总 Nrf2以及 p-Nrf2表达显著上调，提示 JNK、Nrf2相关通路在 LPS 诱导脓毒症脑损伤中可能参与重要的介导作用。