高脂氧化应激对生长抑素分泌及肠、肝基因表达的影响

发布时间：2018-01-15 12:33

本文关键词：高脂氧化应激对生长抑素分泌及肠、肝基因表达的影响　出处：《江南大学》2008年博士论文　论文类型：学位论文

【摘要】： 消化系统是营养物质消化、吸收和代谢的主要器官。长期摄入高脂食物会使机体自由基生成增加,氧化还原状态的改变可能会影响消化系统腺体功能和基因表达,进而影响机体糖、脂代谢。生长抑素作为消化吸收功能的抑制性调节激素对保持机体物质能量代谢平衡具有重要的调节作用。本论文对高能摄入对消化系统氧化还原状态、糖、脂代谢、生长抑素分泌、基因表达的影响以及抗氧化剂硫辛酸的干预作用进行研究。 1.高脂日粮与硫辛酸对小鼠氧化还原状态和自由基水平的影响 72只C57BL/6小鼠随机分为3组,分别饲喂正常日粮、高脂日粮、高脂日粮+0.1%LA。研究随饲喂时间的延长高脂日粮与硫辛酸对小鼠消化系统氧化还原状态和自由基水平的影响,结果表明:高脂日粮喂养小鼠1周,小鼠消化系统自由基水平有所升高,差异不显著(P0.05),随着进食高脂日粮时间的延长,到6周时,小鼠胰腺、肝脏、十二指肠的ROS水平和MDA含量显著提高(P0.05),抗氧化能力显著降低(P0.05),造成机体氧化应激。抗氧化剂LA有效抑制机体氧化还原状态失衡。 2.油酸与硫辛酸对大鼠胃粘膜细胞氧化还原状态和生长抑素分泌的影响体外分离培养大鼠胃黏膜细胞,研究油酸与硫辛酸对大鼠胃粘膜细胞氧化还原状态和生长抑素分泌的影响。结果表明:低浓度的OA(0.1 mmol)能刺激胃粘膜细胞分泌生长抑素(P0.05),ROS含量和胞内Ca2+浓度都有所升高,同时添加LA降低ROS的生成量,SS的分泌量也显著降低;高浓度的OA(1 mmol)显著提高细胞ROS水平(P0.05),GSH/GSSG比值显著降低,MDA含量显著提高,导致细胞氧化损伤,生长抑素的分泌水平也随之降低。去除高浓度(1 mmol)油酸造成细胞氧化损伤组外,SS的分泌量与ROS水平呈非线性回归关系,y=25.645Ln(X)-159.93, R~2=0.8467,结果表明:在一定的范围内ROS可能是OA刺激生长抑素分泌的信号,高浓度的OA氧化损伤胃粘膜细胞,生长抑素分泌量显著降低(P0.05)。 3.高脂日粮与硫辛酸对小鼠生长抑素分泌及血糖、血脂代谢的影响 72只C57BL/6小鼠随机分为3组,分别饲喂正常日粮、高脂日粮、高脂日粮+0.1%LA。研究随饲喂时间的延长高脂日粮与硫辛酸对小鼠生长抑素表达分泌水平以及血糖、血脂代谢的影响,结果表明:在高脂日粮喂养小鼠1周时,小鼠血糖、血脂水平没有明显改变(P0.05)。随着进食高脂日粮时间延长,到3周时,小鼠TG、TC、LDL-C和血糖水平显著升高(P0.05),到6周时,小鼠胰岛素和HOMA-IR指数显著升高(P0.05),出现明显的糖、脂代谢紊乱。添加LA可以显著降低同期高脂日粮小鼠血糖、血脂、胰岛素和HOMA-IR指数。高脂日粮小鼠血浆、胰腺和十二指肠中生长抑素水平有相似的变化趋势:进食高脂日粮1周时,SS显著升高(P0.05),此时十二指肠、胰腺组织的自由基水平有所升高,但差异不显著(P0.05)。随时间的延长,到6周时,高脂日粮小鼠胰腺和十二指肠自由基含量显著升高(P0.05),SS表达分泌水平显著降低(P0.05),表明:短期SS能够通过控制营养物质的消化、吸收而控制消化道自由基水平。但随高脂饲喂时间的延长,高水平的自由基损害SS表达分泌系统,减少分泌量,机体自由基水平剧增。添加LA显著降低长期高脂日粮小鼠血液、组织自由基水平,提高SS表达水平,抑制了机体氧化还原状态的失衡。 4.人高脂血症与血清生长抑素水平和氧化应激关系的探讨选择性别、年龄相当的高脂血症患者和正常个体各28例。测定血清生长抑素水平和抗氧化指标。结果表明:高脂血症患者血糖、胰岛素、HOMA-IR指数、动脉粥样硬化指数和MDA均显著高于正常对照组,SOD、GSH-Px显著低于对照组,存在明显的氧化应激和胰岛素抵抗现象。高脂血症患者血清SS水平显著低于正常对照组(P0.05),SS水平与动脉粥样硬化指数呈显著负相关(r =-0.33, P=0.007)。说明SS分泌降低可能与血脂代谢紊乱密切相关。 5.高脂日粮与硫辛酸对小鼠肠道氧化还原和消化吸收相关功能基因表达的影响利用affymetrix MOE430A基因芯片研究高脂日粮与硫辛酸对小鼠肠道基因表达的影响。结果表明,高脂饲喂引起肠道大量基因表达改变。利用GenMAPP研究高脂和高脂+LA饲喂对小鼠肠道基因表达的影响,结果发现高脂和高脂+LA响应基因显著相关的GO定义相似,主要分为以下几个大类:氧化应激、DNA修复、细胞凋亡、消化吸收、物质转运、免疫反应和信号转导。利用Mappfinder分析了高脂和高脂+LA饲喂显著影响的基因通路,结果表明,高脂日粮小鼠抗氧化酶、物质消化吸收、JAK-STAT信号通路和免疫反应等相关功能基因的表达显著下调,生长抑素的表达水平也显著降低。抗氧化剂LA清除自由基,上调高脂日粮小鼠肠道抗氧化相关功能基因的表达水平,显著提高6周高脂日粮小鼠生长抑素表达水平,进而缓解高脂日粮小鼠肠道氧化损伤。恢复物质消化转运、免疫反应等相关功能基因的表达水平,抑制细胞凋亡通路相关基因表达水平,保持肠道正常生理功能。 6.高脂日粮与硫辛酸对小鼠肝脏氧化还原和脂代谢相关功能基因表达的影响利用Genmapp分析了正常、高脂和高脂+LA饲喂小鼠肝脏显著改变的基因,研究了相关的显著性GO定义,结果表明,高脂饲喂肝脏响应基因主要与脂类代谢、糖代谢、代谢酶和生物转化、应激反应、炎症/免疫反应、AMPK和NF-kB信号通路有关。利用Mappfinder分析了高脂和高脂+LA饲喂小鼠肝脏显著影响的基因通路。结果表明,抗氧化剂LA清除自由基,上调高脂日粮小鼠肝脏抗氧化相关功能基因的表达水平,抑制肝脏氧化还原状态失衡,进而影响AMPK和NF-kB通路基因表达水平,上调脂肪酸?氧化、并下调胆固醇合成通路相关功能基因的表达水平,参与脂类代谢过程的调节。氧化应激抑制AMPK通路相关基因表达,LA解除肝脏氧化应激上调AMPK通路基因表达水平,AMPK促进脂肪酸氧化,并抑制肝内的成脂过程。氧化应激激活NF-kB通路,提高TNF-α的表达水平。TNF-α是肝脏内抑制胰岛素信号传导的关键物质。硫辛酸显著下调NF-kB通路基因的表达,降低TNF-αmRNA,进而改善高脂日粮小鼠糖、脂代谢代谢紊乱。
[Abstract]:The digestive system is nutrient digestion, absorption and metabolism of main organs. The long-term intake of high fat food will make the body free radicals generated increased redox state changes may affect the digestive gland function and expression of genes, thereby affecting the glucose, lipid metabolism. Somatostatin as the digestion and absorption of hormone has inhibitory function an important role to keep the material energy metabolism balance. The high energy intake reduction state on the digestive system of oxidation of sugar, lipid metabolism, somatostatin secretion, gene expression and the effects of antioxidant lipoic acid intervention effect were studied.
Effect of 1. high fat diet and lipoic acid on redox state and free radical level in mice
72 C57BL/6 mice were randomly divided into 3 groups, were fed with normal diet, high fat diet, high fat diet +0.1%LA. study with feeding time prolonged high fat diet and lipoic acid reduction effect, and the level of free radicals on the oxidation of the digestive system of mice showed that mice fed high-fat diet for 1 weeks the level of free radicals, the digestive system of mice was increased, the difference was not significant (P0.05), with the extension of eating high-fat diet time, at 6 weeks, mice pancreas, liver, ROS level and MDA content in duodenum increased significantly (P0.05), the antioxidant capacity was significantly lower (P0.05), caused by oxidative stress. Antioxidant LA can effectively suppress the redox imbalance in the body.
Effects of 2. oleic acid and lipoic acid on the redox state and somatostatin secretion of gastric mucosa in rats
Isolation and culture of rat gastric mucosal cells in vitro, study of oleic acid and lipoic acid reduction effect and somatostatin secretion on oxidation of rat gastric mucosal cells. The results showed that the low concentration of OA (0.1 mmol) can stimulate the secretion of gastric mucosal cells of somatostatin (P0.05), ROS content and intracellular Ca2+ concentration increased. At the same time, the addition of LA reduced the production of ROS, SS secretion was significantly lower; the high concentration of OA (1 mmol) significantly increased the level of ROS cells (P0.05), GSH/GSSG ratio was significantly decreased, MDA content increased significantly, resulting in oxidative damage to cells, secretion of somatostatin also decreases. The removal of high concentration (1 mmol) oleic acid induced oxidative stress group, secretion of SS and ROS showed a nonlinear regression relationship between y=25.645Ln (X) -159.93, R~2=0.8467, the results showed that: in a certain range of ROS OA may stimulate the growth of somatostatin secretion signal, high concentration of OA The secretion of somatostatin was significantly decreased by oxidative damage of gastric mucosa cells (P0.05).
3. effects of high fat diet and lipoic acid on somatostatin secretion, blood glucose and blood lipid metabolism in mice
72 C57BL/6 mice were randomly divided into 3 groups, were fed with normal diet, high fat diet, high fat diet +0.1%LA. study with feeding time prolonged high fat diet and lipoic acid secretion and expression of somatostatin on blood glucose, lipid metabolism of mice, the results showed that: in high fat diet fed mice at 1 weeks, blood glucose, blood lipid levels did not change significantly (P0.05). With the extension of eating high-fat diet time, at 3 weeks, mice TG, TC, LDL-C and blood glucose levels were significantly increased (P0.05), at 6 weeks, insulin and HOMA-IR index of mice was significantly increased (P0.05), apparent sugar and fat metabolism disorder. Addition of LA can significantly reduce the period of high fat diet mice blood glucose, blood lipid, insulin and HOMA-IR index. The high fat diet fed mouse plasma, pancreatic and duodenal somatostatin level have the same trend: eating a high-fat diet for 1 weeks, SS was significantly increased (P0.05), The duodenum, the level of free radicals in pancreatic tissue increased, but the difference was not significant (P0.05). With the extension of time to 6 weeks, high-fat diet mice pancreas and duodenum content of free radicals increased significantly (P0.05), SS expression level was significantly lower (P0.05), showed that SS can control through the short term nutrient digestion, absorption and control the level of free radical in digestive tract. But with prolonged high fat feeding time, free radical damage and high level of SS expression and secretion system, reduce the secretion level of free radicals in the body dramatically. Adding LA significantly reduced long-term high-fat diet mice blood free radical level of the organization, improve the expression of SS the level of inhibition of the redox state imbalance.
The relationship between hyperlipidemia and serum somatostatin level and oxidative stress in 4. people
Choose the gender, age of hyperlipidemia patients and normal individuals in all 28 cases. The serum levels of somatostatin and antioxidant index. The results showed that the blood glucose of patients with hyperlipidemia, insulin, HOMA-IR index, MDA index and atherosclerosis were significantly higher than the normal control group, SOD, GSH-Px was significantly lower than the control group, oxidative stress and insulin obviously the resistance phenomenon. Patients with hyperlipidemia serum SS level was significantly lower than the normal control group (P0.05), SS was negatively correlated with the level of atherosclerosis index (R =-0.33, P=0.007). The results showed that SS secretion may be closely related to lipid metabolism disorder.
Effect of 5. high fat diet and lipoic acid on the expression of functional genes related to redox and digestion and absorption of intestinal tract in mice
Effect on the expression of intestinal Affymetrix gene by MOE430A gene chip of high fat diet and lipoic acid. The results showed that the expression of a large number of genes change caused by intestinal high-fat feeding. Effect on the expression of intestinal GenMAPP gene by using of high fat and high fat fed +LA, found that high fat and high fat +LA GO defines significant response related genes are similar, mainly divided into the following categories: oxidative stress, DNA repair, apoptosis, digestion and absorption, transport, immune response and signal transduction. To analyze the Mappfinder gene pathway, high fat and high fat fed +LA significantly affected the results showed that the high fat diet mice antioxidant substances digestion and absorption, the expression of related function of JAK-STAT signaling pathway and the immune response genes were down regulated and the expression level of somatostatin were significantly decreased. The antioxidant LA free radical scavenging on high fat diet The expression level of related genes in mice intestinal antioxidant function, significantly increased 6 weeks of high-fat diet mice somatostatin expression levels, and alleviate the high-fat diet mice intestinal oxidative damage. Recovery of digestive transport, the expression level of related functions of immune response genes, inhibiting cell apoptosis pathway related gene expression, maintain normal intestinal physiology function.
Effect of 6. high fat diet and lipoic acid on the expression of functional genes related to redox and lipid metabolism in mice liver
Genmapp analysis of the use of normal, high fat and high fat fed mice liver +LA significantly changed genes studied was the definition of GO, the related results show that high fat fed liver response genes were mainly associated with lipid metabolism, glucose metabolism, metabolism and biotransformation, stress reaction, inflammatory / immune response, AMPK and NF-kB the signal transduction pathway. To analyze the Mappfinder gene pathway of high fat and high fat fed mice liver +LA significantly affected. The results showed that the antioxidant LA free radical scavenging activity, the expression of water related upregulation of high fat diet fed mouse liver antioxidant gene, inhibition of redox state imbalance in liver oxidation, and effects of AMPK and NF-kB pathway gene expression level upregulation of fatty acid oxidation,?, and down regulate the expression level of the cholesterol synthesis pathway related genes, regulate lipid metabolism. Oxidative stress inhibits AMPK pathway related gene expression, LA Relieve hepatic oxidative stress and up regulation of AMPK pathway gene expression level, AMPK promotes fatty acid oxidation and inhibit lipid formation in liver. Oxidative stress activates the NF-kB pathway, improve the expression level of TNF- alpha.TNF- alpha is the key material in the liver of inhibition of insulin signal transduction. Lipoic acid significantly downregulated expression of NF-kB pathway genes, decreased TNF- a mRNA, in order to improve the high fat diet mice, lipid metabolism disorder.

【学位授予单位】：江南大学
【学位级别】：博士
【学位授予年份】：2008
【分类号】：R363

【引证文献】