酮病奶牛血浆Leptin动态变化与脂肪Leptin及其受体转录水平的研究

发布时间：2019-01-02 08:31

【摘要】：奶牛在产后处于能量负平衡状态,使体脂大量动员,进而导致酮病。酮病牛生产、繁殖性能下降,甚至被淘汰。瘦素(Leptin)是由白色脂肪合成分泌的激素,能够抑制摄食行为,参与能量平衡、脂肪代谢的调控。本研究旨在了解血浆Leptin水平与奶牛酮病的相互关系以及添加β-羟丁酸、Leptin.胰岛素对脂肪Leptin相关基因转录的影响。实验选择16头待产母牛,自产前1周起至产后第7周逐周进行血浆Leptin等血液指标检测,结果表明：酮病牛具有低血浆Leptin.低葡萄糖、高酮体、高游离脂肪酸水平的代谢特点,与非酮病牛相比差异显著。奶牛分娩后血浆Leptin水平逐渐升高,在产后第2周至第4周,酮病牛的Leptin含量超过非酮病牛,但差异不显著。该时期酮病牛的酮体、游离脂肪酸水平极显著高于非酮病牛的水平。体外实验对皮下脂肪、肠系膜脂肪和肾周脂肪组织分别添加不同浓度的β-羟丁酸(0.5、1.0、3.0、5 mM/L),Leptin(10.50、100ng/ml).和胰岛素(10、50、100 nM/L),检测Leptin及其三个受体(ObRa、ObRb. ObRc)的mRNA水平。结果表明：在三种脂肪中均未检测到ObRa的表达。皮下脂肪对β-羟丁酸浓度变化最为敏感,低浓度的β-羟丁酸(0.5、1.0 mM/L)极显著上调皮下脂肪Leptin、ObRb和ObRc转录水平；高浓度β-羟丁酸(3.0、5.0 mM/L)下调Leptin mRNA表达,极显著降低对ObRb和ObRc的上调作用。肾周脂肪中,β-羟丁酸浓度变化仅对ObRc mRNA有显著作用。各浓度Leptin对皮下、肾周脂肪的Leptin及ObRb、ObRc mRNA水平有趋同效应。皮下脂肪的Leptin及ObRb、ObRc mRNA随胰岛素浓度升高而降低,肾周脂肪则相反。三种药物各浓度均下调肠系膜脂肪中的Leptin及其受体mRNA表达,其中胰岛素作用显著。结论,低血浆Leptin水平与酮病有关。β-羟丁酸升高会影响Leptin及其受体mRNA的表达。不同部位脂肪的Leptin分泌与自身调节存在差异,皮下脂肪是最主要的Leptin分泌位点,且对β-羟丁酸最为敏感。肾周脂肪Leptin相关基因的转录变化不大,维持在一定水平。
[Abstract]:Cows in postpartum negative energy balance, body fat mobilization, and then lead to ketosis. Ketosis cattle production, reproductive performance decline, or even be eliminated. Leptin (Leptin) is a hormone synthesized and secreted by white fat, which can inhibit feeding behavior, participate in the regulation of energy balance and fat metabolism. The purpose of this study was to investigate the relationship between plasma Leptin level and ketogenic disease in dairy cattle and to add 尾 -hydroxybutyric acid, Leptin.. Effects of insulin on the transcription of adipose Leptin related genes. Blood indexes such as plasma Leptin were measured from 1 week before delivery to 7 weeks postpartum. The results showed that ketosis cattle had low plasma Leptin.. The metabolic characteristics of low glucose, high ketone body and high free fatty acid levels were significantly different from those of non-ketosis cattle. The plasma Leptin level increased gradually after parturition, and the Leptin content of ketosis cattle was higher than that of non-ketosis cattle from the 2nd to 4th week postpartum, but the difference was not significant. The level of free fatty acids in ketosis cattle was significantly higher than that in non ketosis cattle. In vitro, subcutaneous fat, mesenteric fat and perirenal adipose tissue were supplemented with different concentrations of 尾 -hydroxybutyric acid (0.5 ~ 1.0 ~ 3.0 mM/L), Leptin (10.50100ng/ml). And insulin (1050100 nM/L). Leptin and its three receptors (ObRa,ObRb.) were detected. ObRc). The results showed that the expression of ObRa was not detected in all three fats. The subcutaneous fat was most sensitive to the change of 尾 -hydroxybutyric acid concentration, and the low concentration of 尾 -hydroxybutyric acid (0.5 ~ 1.0 mM/L) significantly upregulated the transcription levels of Leptin,ObRb and ObRc in subcutaneous fat. High concentration of 尾 -hydroxybutyric acid (3.0 mM/L) down-regulated the expression of Leptin mRNA, and significantly decreased the up-regulation of ObRb and ObRc. In perirenal fat, the change of 尾-hydroxybutyric acid concentration only had a significant effect on ObRc mRNA. The concentration of Leptin had a similar effect on the levels of Leptin and ObRb,ObRc mRNA in subcutaneous and perirenal fat. The Leptin and ObRb,ObRc mRNA of subcutaneous fat decreased with the increase of insulin concentration, whereas the perinephric fat decreased. All the three drugs down-regulated the expression of Leptin and its receptor mRNA in mesenteric fat, in which insulin played a significant role. Conclusion: low plasma Leptin level is associated with ketosis. 尾 -hydroxybutyric acid (尾 -hydroxybutyric acid) may affect the expression of Leptin and its receptor mRNA. The secretion of Leptin in different parts of fat was different from that of self-regulation. Subcutaneous fat was the most important Leptin secretion site, and was most sensitive to 尾 -hydroxybutyric acid (尾 -hydroxybutyric acid). The transcriptional changes of Leptin related genes in perirenal fat were not changed and maintained at a certain level.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S858.23

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