壳聚糖对高脂膳食小鼠氧化应激及糖代谢的影响

发布时间：2018-02-23 17:18

本文关键词： 壳聚糖高脂膳食氧化应激糖代谢　出处：《江南大学》2017年硕士论文　论文类型：学位论文

【摘要】：本文通过长期(16周)对小鼠喂食高脂膳食,研究壳聚糖的添加对由高脂膳食引起的氧化应激以及糖代谢紊乱的影响,并对其作用机理进行初步研究,为高脂膳食引发氧化应激和糖代谢紊乱及壳聚糖作为血糖调节营养素研究提供理论基础。选取6周龄SPF级C57BL/6J雄性小鼠60只,随机分为5组(每组12只),分别饲喂正常膳食、高脂(无添加、添加低分子量壳聚糖(5%)、高分子量壳聚糖(5%)、二甲双胍(5%))膳食,饲养过程中测定各组小鼠体重、摄食量、空腹血糖、葡萄糖耐受、胰岛素耐受情况,饲养16周后处死,测定血浆中甘油三酯、总胆固醇、高密度脂蛋白胆固醇、低密度脂蛋白胆固醇的含量;检测肝脏中甘油三酯、总胆固醇、肝脂酶和脂蛋白脂肪酶水平;检测肝脏中总抗氧化能力、过氧化氢酶和超氧化物歧化酶活性、丙二醛;对肝脏、胰腺的组织结构进行观察;运用实时相对定量逆转录聚合酶链反应(RT-PCR)技术和Western Blot检测肝脏中氧化应激及糖异生信号通路中相关基因和蛋白表达。实验结果表明:一、16周的高脂膳食对小鼠日常摄食量无显著影响,但会造成体重显著增加,壳聚糖可有效缓解该现象,高分子量壳聚糖效果略好;二、16周高脂膳食饲喂会造成小鼠肝脏脂质合成相关酶ACC1表达水平显著上升,导致小鼠血清中的总胆固醇、低密度脂蛋白胆固醇含量显著增加,肝脏中总胆固醇含量显著增加,壳聚糖可显著缓解该现象,高分子量壳聚糖效果优于低分子量壳聚糖;三、16周高脂膳食对小鼠肝脏和胰腺组织结构有一定破坏,导致组织出现脂肪空泡、脂肪变性,壳聚糖可保护肝脏和胰腺组织结构;四、高脂膳食诱导小鼠氧化还原应激,氧化酶(过氧化氢酶、超氧化物歧化酶等)含量降低,丙二醛含量上升,氧化还原环境的稳态遭到破坏,肝脏转录因子NF-E2相关因子-2 mRNA表达水平略有上升,其调控的抗氧化酶(血红素氧合酶1、醌氧化还原酶-1)mRNA表达水平显著下降,糖原合成酶激酶-3βmRNA相对表达量显著上升。壳聚糖可改善体内的氧化应激水平,缓解由高脂膳食造成的损伤;五、16周高脂膳食导致的糖代谢紊乱主要是因为肝脏氧化应激引起磷酸烯醇式丙酮酸羧激酶和葡萄糖6磷酸酶表达水平上升,最终导致肝脏和肌肉糖代谢紊乱;壳聚糖可调控叉头转录因子-1和肝细胞核因子-4α等基因表达水平,下调磷酸烯醇式丙酮酸羧激酶和葡萄糖6磷酸酶表达水平。结论:壳聚糖可改善由高脂膳食造成的氧化应激和糖代谢紊乱,高分子壳聚糖效果略好。
[Abstract]:The effects of chitosan supplementation on oxidative stress and glucose metabolism disorder induced by high fat diet were studied in mice fed with high fat diet for a long period of 16 weeks. To provide a theoretical basis for the study of oxidative stress and glucose metabolism disorder induced by high fat diet and chitosan as a glycemic regulating nutrient, 60 SPF grade C57BL / 6J male mice of 6 weeks old were randomly divided into 5 groups (12 rats in each group, fed with normal diet respectively), and 6 weeks old C57BL / 6J male mice were randomly divided into 5 groups (12 rats in each group). High fat diet (no addition, low molecular weight chitosan, high molecular weight chitosan, metformin) diet, body weight, food intake, fasting blood glucose, glucose tolerance, insulin tolerance in each group were measured. The levels of triglyceride, total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol in plasma, triglyceride, total cholesterol, hepatic lipase and lipoprotein lipase in liver were measured. Total antioxidant capacity, catalase and superoxide dismutase activity, malondialdehyde (MDA), liver and pancreas were observed. Real-time relative quantitative reverse transcription polymerase chain reaction (RT PCR) and Western Blot were used to detect the expression of genes and proteins related to oxidative stress and glycosylated signal pathway in liver. There was no significant effect on regular food intake. However, it could significantly increase body weight, which could be effectively alleviated by chitosan. The effect of high molecular weight chitosan was slightly better, and the level of ACC1 expression of liver lipid-synthase related enzymes was significantly increased in mice fed with high-fat diet for 16 weeks. The results showed that the total cholesterol, low density lipoprotein cholesterol and liver total cholesterol in serum of mice were significantly increased. Chitosan could alleviate this phenomenon, and the effect of high molecular weight chitosan was better than that of low molecular weight chitosan. The liver and pancreas tissue structure of mice was damaged by high fat diet for 16 weeks, resulting in fat vacuole, fatty degeneration, chitosan could protect the liver and pancreas tissue structure. 4, high fat diet induced redox stress in mice. The content of oxidase (catalase, superoxide dismutase, etc.) decreased, the content of malondialdehyde increased, the homeostasis of redox environment was destroyed, and the expression level of liver transcription factor NF-E2 related factor 2 mRNA increased slightly. Its regulated antioxidant enzymes (heme oxygenase 1, quinone redox enzyme -1 mRNA expression level decreased significantly, glycogen synthase kinase-3 尾 mRNA expression increased significantly. Chitosan can improve the oxidative stress level in vivo. The disorder of glucose metabolism caused by high fat diet at the fifth week of 16 weeks was mainly due to the increased expression of phosphoenolpyruvate carboxykinase and glucose-6 phosphatase induced by oxidative stress in liver. Chitosan can regulate the expression level of forkhead transcription factor-1 and liver nuclear factor-4 伪, which leads to the disorder of glucose metabolism in liver and muscle. Conclusion: chitosan can improve oxidative stress and glucose metabolism disorder caused by high fat diet, and the effect of polymer chitosan is better than that of high fat diet, but the expression of phosphoenolpyruvate carboxykinase and glucose-6 phosphatase is down-regulated.
【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R151

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