LPS对动物肝脏线粒体功能的影响以及α-硫辛酸的缓解作用

发布时间：2018-01-19 18:39

本文关键词： 硫辛酸 LPS 肝脏 mtDNA　出处：《南京农业大学》2015年硕士论文　论文类型：学位论文

【摘要】：在目前的规模化养猪场中,炎症感染不可避免的经常存在。炎症可以引起不可逆肝损伤。因此抑制肝脏的炎症对于机体的健康异常重要。α-硫辛酸(LA),一种天然的短链脂肪酸,也是线粒体中丙酮酸脱氢酶复合体和α-酮戊二酸脱氢酶复合体的辅酶。它在线粒体代谢当中发挥重要作用,但LA是否可以通过影响线粒体功能来缓解炎症引起的肝脏损伤,以及其可能的机制并不清楚。此外,对于猪的炎症感染研究,大多数研究都关注在免疫反应,鲜少有研究关注猪肝脏线粒体的功能变化。因此,在本研究分两部分:第一部分以小鼠为模型,探讨炎症状况下,LA对肝脏线粒体的作用以及机制;第二部分以生长猪为模型,探讨炎症对于猪肝脏线粒体的影响。1 LA对LPS引起的小鼠肝脏线粒体损伤的缓解作用及其机制以小鼠为模型,随机分为三组:Con组注射5d生理盐水;LPS组注射5d生理盐水,并在第五天注射1h后注射5mg/kgLPS;LA+LPS组注射5d100mg/kg的LA,并同样在第五天注射1h后注射5mg/kgLPS。6h,24h后采样,检测肝脏损伤,能量代谢和线粒体功能以及调控。结果显示,相对于LPS组,LA下调了血浆中谷丙转氨酶和谷草转氨酶含量,缓解了肝脏损伤。肝脏ATP、NADH含量,大多数线粒体DNA(mtDNA)编码基因的基因表达,以及线粒体复合物I,IV和V活性也都相对于LPS组显著上调。去乙憸化酶3(Sirt 3)对于调节线粒体代谢至关重要,LA同样上调了 Sirt 3的表达。关于mtDNA编码基因表达的调控,本研究表明mtDNAD-loop区域的甲基化水平没有变化。然而,相对于LPS组,LA上调了糖皮质激素受体(GR)在肝脏的蛋白表达,同时也上调了 GR在mtDNA D-loop区域的结合。以上结果表明在炎症状态下,LA通过提高线粒体功能来发挥肝脏保护作用,GR通过上调其在mtDNA D-loop区域的结合参与了此过程。2 LPS对猪肝脏线粒体功能的影响以生长猪为模型,随机分为两组:Con组注射生理盐水,LPS组注射15 μg/kg LPS,6h后采样检测肝脏损伤,能量代谢以及线粒体功能。结果显示,LPS处理后血浆谷草转氨酶含量显著上调,引起猪肝脏损伤。且炎症因子TNF-α,NF-κB和IL-1α在肝脏中基因表达显著上调。虽然肝脏中甘油三酯和糖原含量显著下调,能量消耗增加,但是肝脏中ATP、ADP和AMP以及能荷均没有受到LPS的影响。并且在本研究炎症状态下,mtDNA编码基因的表达以及线粒体复合物IV和V的活力也没有发生显著变化。
[Abstract]:In the current large-scale pig farms, inflammatory infection is inevitable. Inflammation can cause irreversible liver damage. Therefore, inhibiting liver inflammation is extremely important for the health of the body. 伪 -lipoxylic acid (伪 -lipoic acid). A natural short-chain fatty acid, also a coenzyme of pyruvate dehydrogenase complex and 伪 -ketoglutarate dehydrogenase complex in mitochondria, which plays an important role in mitochondrial metabolism. However, it is not clear whether LA can alleviate liver injury caused by inflammation by affecting mitochondrial function and its possible mechanism. In addition, most studies on inflammatory infection in pigs focus on immune response. Few studies have focused on the functional changes of hepatic mitochondria in pigs. Therefore, this study is divided into two parts: the first part is a mouse model to explore the effect and mechanism of LA on liver mitochondria under inflammatory condition; In the second part, the effects of inflammation on the mitochondria of pig liver were studied in order to investigate the effects of inflammation on mitochondria damage induced by LPS in mice and its mechanism. They were randomly divided into three groups: the control group was injected with saline for 5 days. In LPS group, normal saline was injected for 5 days, and 5 mg / kg LPS was injected 1 hour after injection on 5th days. The LA LPS group was injected with 5 d 100 mg / kg LA. the same time was injected 1 h on day 5th, and then injected 5 mg / kg LPS.6 h for 24 h, then the liver injury was detected. Energy metabolism, mitochondrial function and regulation. The results showed that LA decreased plasma alanine aminotransferase and alanine aminotransferase contents, and alleviated liver injury and liver ATP compared with LPS group. The NADH content, the gene expression of most mtDNA-encoded genes, and the activities of mitochondrial complex IIV and V were also significantly increased compared with those of LPS group. 皙The expression of Sirt 3 was also upregulated by LA, which was important for regulating mitochondrial metabolism. The regulation of mtDNA coding gene expression was also discussed. This study showed that the methylation level in the mtDNAD-loop region did not change. However, LA upregulated the expression of glucocorticoid receptor GRG in the liver compared with the LPS group. The binding of gr to mtDNA D-loop region was also up-regulated. The above results suggest that LA plays a role in liver protection by improving mitochondrial function in inflammatory state. Gr participated in this process by upregulating its binding to mtDNA D-loop region. 2. 2 LPS was involved in the effect of GR on the function of hepatic mitochondria in pigs. The rats were randomly divided into two groups: control group (n = 10) and LPS group (n = 6). Liver injury, energy metabolism and mitochondrial function were measured after injection of 15 渭 g / kg LPSN for 6 h. Plasma glutamic oxaloacetic transaminase content was significantly up-regulated after LPS treatment, resulting in liver injury and inflammatory factor TNF- 伪. The gene expression of NF- 魏 B and IL-1 伪 was significantly up-regulated in the liver. Although the contents of triglyceride and glycogen decreased significantly and the energy consumption increased in the liver, ATP was found in the liver. ADP, AMP and energy charge were not affected by LPS. The expression of mtDNA coding gene and the activity of mitochondrial complexes IV and V did not change significantly.
【学位授予单位】：南京农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S852.3

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