EGCG对LPS诱导的p38 MAPK信号转导作用研究

发布时间：2018-04-18 16:41

本文选题：表没食子儿茶素没食子酸酯(EGCG) + p38丝裂原活化蛋白激酶　；参考：《南京师范大学》2005年硕士论文

【摘要】：表没食子儿茶素没食子酸酯(EGCG)是绿茶多酚的主要活性成分,近年研究表明EGCG除具抗癌、抗氧化等活性外,尚具显著抗炎活性,但其作用机理研究尚少。本文从p38 MAPK信号通路及炎症因子表达方面研究了EGCG对脂多糖(LPS)介导炎症过程的作用,在动物急性肺损伤(ALI)模型的干预作用方面也探讨了EGCG抗炎作用的可能机理。 1.体外EGCG对LPS的直接作用: 本研究首次应用透射电镜观察及内毒素鲎实验检测法研究EGCG对LPS的直接作用,结果表明EGCG对INS的结构和量无显著影响,提示EGCG对LPS无直接作用。 2.EGCG对LPS激活的小鼠巨噬细胞的作用: 以LPS刺激小鼠巨噬细胞株RAW264.7,应用Western blotting法检测磷酸化p38 MAPK的表达,EMSA法检测细胞TNF-a和PGE_2的表达。结果表明EGCG对LPS激活的p38 MAPK磷酸化,TNF-a和PGE_2的表达均具明显抑制作用。对小鼠腹腔巨噬细胞的免疫细胞化学实验同样表明了EGCG对INS激活的p38MAPK通路的干预作用。 3.EGCG对小鼠油酸型ALI模型的干预作用: 本研究首次应用小鼠油酸型ALI动物模型研究EGCG的体内效应。EGCG于造模前给药,剂量为6、12和25mg/kg,造模后检测小鼠肺组织p38 MAPK磷酸化和血清TNF-a的表达,结果表明EGCG对肺组织p38 MAPK磷酸化和血清TNF-a表达具有抑制作用。提示EGCG对油酸型ALI具有干预作用。本研究结果表明EGCG对LPS无直接影响,可通过干预体内信号通路发挥其抑制作用,p38 MAPK可能是EGCG抑制LPS诱导巨噬细胞表达TNF-a的重要通路之一。另外,EGCG对油酸型小鼠急性肺损伤有一定保护作用,其作用机制可能与其能抑制p38 MAPK的磷酸化,并减少TNF-a的合成与释放有关。
[Abstract]:Epigallocatechin gallate (EGCG) is the main active component of green tea polyphenols. Recent studies have shown that EGCG not only has anti-cancer and anti-oxidation activities, but also has significant anti-inflammatory activity.In this paper, the effects of EGCG on lipopolysaccharide (LPS) -mediated inflammation were studied from the aspects of p38 MAPK signaling pathway and inflammatory factor expression. The possible mechanism of EGCG anti-inflammatory action was also discussed in the animal model of acute lung injury.1.Direct effect of EGCG on LPS in vitro:In this study, the direct effect of EGCG on LPS was studied by transmission electron microscopy and endotoxin Limulus test for the first time. The results showed that EGCG had no significant effect on the structure and quantity of INS, suggesting that EGCG had no direct effect on LPS.Effects of 2.EGCG on LPS activated mouse macrophages:Mouse macrophage cell line RAW264.7 was stimulated by LPS. The expression of phosphorylated p38 MAPK was detected by Western blotting method and the expression of TNF-a and PGE_2 was detected by EMSA method.The results showed that EGCG significantly inhibited the expression of LPS activated p38 MAPK phosphorylated TNF-a and PGE_2.The immunocytochemistry of murine peritoneal macrophages also demonstrated the effect of EGCG on the p38MAPK pathway activated by INS.The intervention effect of 3.EGCG on oleic acid type ALI model in mice:In this study, we used oleic acid ALI animal model to study the in vivo effect of EGCG. EGCG was administered at doses of 6 mg / kg and 25 mg / kg. The phosphorylation of p38 MAPK and the expression of TNF-a in serum were detected after the establishment of the model.The results showed that EGCG could inhibit the phosphorylation of p38 MAPK and the expression of serum TNF-a in lung tissues.The results suggest that EGCG can interfere with oleic acid type ALI.The results suggest that EGCG has no direct effect on LPS, and p38 MAPK may be one of the important pathways by which EGCG inhibits the expression of TNF-a in macrophages induced by LPS.In addition, EGCG has a protective effect on acute lung injury in oleic acid mice, and its mechanism may be related to the inhibition of phosphorylation of p38 MAPK and the reduction of synthesis and release of TNF-a.
【学位授予单位】：南京师范大学
【学位级别】：硕士
【学位授予年份】：2005
【分类号】：R363

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