甲状腺激素代谢相关microRNAs对小鼠肥胖易感性的影响

发布时间：2018-06-01 11:04

本文选题：高脂膳食 + 肥胖　；参考：《江南大学》2015年硕士论文

【摘要】：目的:高脂膳食条件下不同个体对肥胖表现出不同的易感性,但具体机制未明。甲状腺激素是机体能量代谢和脂质代谢的重要调节因子,其代谢可能受到micro RNAs的调节。因此,本文主要从micro RNAs影响甲状腺激素代谢角度探讨了肥胖和肥胖抵抗机体表型差异出现的可能原因。通过饲喂高脂膳食建立肥胖和肥胖抵抗表型,探究高脂膳食诱导的甲状腺激素代谢及相关micro RNAs的表达差异对小鼠肥胖和肥胖抵抗表型产生的可能影响。方法:120只C57BL/6雄性小鼠分别饲喂正常膳食(n=30,C组)和高脂膳食(n=90,HFD组)。7周时根据小鼠体重将HFD组分为肥胖组(体重最高的1/3,DIO)和肥胖抵抗组(体重最低的1/3,DIO-R)。分组后从C组、DIO组和DIO-R组中随机选出10只分别在7周、17周和27周时处死以评价甲状腺激素在高脂膳食饲喂早期、中期和晚期时对小鼠肥胖易感性的影响。用CLAMS动物代谢监测系统测定小鼠的代谢状况,分别测定血浆中甲状腺激素水平和血脂水平。7周时对小鼠的肝脏进行micro RNAs测序,并采用荧光定量PCR验证各个周期中甲状腺激素代谢相关micro RNAs的m RNA水平,同时测定肝脏中Ⅰ型脱碘酶(D1)和甲状腺激素受体β(TRβ)以及脂代谢相关基因的m RNA水平。Western blot测定小鼠肝脏中D1和TRβ的蛋白水平。分别对小鼠肝脏中micro RNAs的水平和D1、TRβ的表达及肝脏中micro RNAs的水平和血浆中甘油三酯(TG)、总胆固醇(TC)含量进行相关性分析。结果:高脂膳食短期饲喂(7周)时,DIO组的体重比C组的体重高了1.2倍以上,达到了肥胖的标准即造模成功,而C组和DIO-R组体重无显著差异(P0.05)。根据测序结果筛选出三组小鼠肝脏中差异表达并能作用于甲状腺激素代谢的micro RNAs:靶作用于D1翻译过程的mi R-383,靶作用于TRβ转录过程的mi R-34a和mi R-146b。高脂膳食短期饲喂时,DIO组和DIO-R组肝脏中mi R-383,mi R-34a和mi R-146b的水平均低于C组。与DIO-R组相比,DIO组的血浆甲状腺素(T4)和甲状腺激素(T3)水平,肝脏中D1的蛋白水平和FAS的表达显著高于DIO-R组,而TRβ的m RNA和蛋白水平及CPT1α、PGC1α和CYP7A1的表达显著低于DIO-R组(P0.05)。DIO组的血浆TG水平显著高于DIO-R组(P0.05),而两组间TC水平无显著差异(P0.05)。高脂膳食饲喂中期(17周)时,DIO组肝脏中mi R-383、mi R-34a和mi R-146b的表达均显著高于DIO-R组,且D1,TRβ蛋白水平和血浆T3水平均显著低于DIO-R组(P0.05)。DIO组肝脏中FAS的表达仍显著高于DIO-R组;而DIO组肝脏中CPT1α、PGC1α和CYP7A1的的表达显著低于DIO-R组(P0.05)。DIO组的体重、血浆TG水平和TC水平均显著高于DIO-R组(P0.05)。高脂膳食饲喂后期(27周)时,DIO组肝脏中mi R-383显著高于DIO-R组,肝脏中D1的蛋白水平和血浆T3水平显著低于DIO-R组(P0.05)。三组小鼠肝脏中mi R-34a、mi R-146b和TRβ及CPT1α、PGC1α和CYP7A1的表达无显著差异(P0.05)。DIO组的体重、FAS的表达量、TG、TC和LDL-C含量均显著高于DIO-R组(P0.05)。相关性分析表明:肝脏中mi R-383和D1的蛋白水平呈显著负相关(P0.05);肝脏中mi R-34a和TRβ的m RNA水平及蛋白水平均呈显著负相关(P0.05);肝脏中mi R-146b和TRβ的m RNA水平及蛋白水平均呈显著负相关(P0.05)。肝脏中mi R-34a和血浆中TG和TC含量均呈显著正相关(P0.05);mi R-146b和血浆中TG和TC含量均正相关,但不显著(P0.05);mi R-383和血浆中TG含量显著正相关(P0.05),而mi R-383和血浆中TC含量正相关但不显著(P0.05)。结论:高脂膳食饲喂在不同周期对DIO-R和DIO组小鼠肝脏中甲状腺激素代谢相关micro RNAs表达的影响是不同的。与DIO-R组相比,高脂膳食饲喂早期DIO组小鼠肝脏中mi R-383的表达受到抑制,使得肝脏中D1的表达升高;而到高脂饲喂中期和后期时DIO组小鼠肝脏中mi R-34a和mi R-146b的表达升高,使得肝脏中TRβ的表达受到抑制。DIO-R和DIO组小鼠肝脏中mi R-383,mi R-34a和mi R-146b表达的不同变化使T3靶基因中脂代谢相关基因的表达出现差异,最终导致DIO组小鼠体重显著高于DIO-R组,出现了肥胖和肥胖抵抗表型的差异。
[Abstract]:Objective: under the condition of high fat diet, different individuals have different susceptibility to obesity, but the specific mechanism is not clear. Thyroid hormone is an important regulator of the body's energy metabolism and lipid metabolism, and its metabolism may be regulated by micro RNAs. Therefore, this paper mainly discusses the obesity and fertilizer from the effect of micro RNAs on the metabolic angle of thyroid hormone. The possible causes of the phenotypic difference of fat resistance. Establish obesity and obesity resistance phenotype by feeding high fat diet, explore the possible effects of high fat diet induced thyroid hormone metabolism and the difference of micro RNAs expression on the obesity and obesity resistance phenotype of mice. Methods: 120 male C57BL/6 mice were fed to normal. Dietary (n=30, C) and high fat diet (group n=90, HFD) were divided into obese group (the highest weight 1/3, DIO) and the obesity resistance group (the lowest weight 1/3, DIO-R) according to the weight of the mice (the highest weight 1/3, DIO) and the obese group (the HFD group) at.7 weeks. The 10 rats were randomly selected from the C group, the DIO group and the 27 weeks to evaluate the thyroid hormone in the high fat diet. The effects of early, middle and late stage on the susceptibility to obesity in mice. The metabolic status of mice was measured by CLAMS animal metabolism monitoring system. The serum thyroid hormone level and blood lipid level were measured by micro RNAs sequencing at.7 weeks respectively. The fluorescence quantitative PCR was used to verify the thyroid hormone metabolism related MI in each cycle. The level of M RNA in cro RNAs and the determination of the level of D1 and TR beta in the liver of mice were measured by M RNA level.Western blot in the liver of type I deiodine (D1) and thyroid hormone receptor beta (TR beta), and the level of M RNA in the lipid metabolism related genes. Results: the content of triglyceride (TG) and total cholesterol (TC) was analyzed. Results: when high fat diet was fed for 7 weeks, the weight of group DIO was more than 1.2 times higher than that of group C, and the standard of obesity was successful, while the weight of C group and DIO-R group had no significant difference (P0.05). According to the sequencing results, the difference tables of liver in three groups of mice were screened. The micro RNAs: target that can function in the thyroid hormone metabolism acts on the MI R-383 of the D1 translation process. When the target is fed on the MI R-34a and MI R-146b. high fat diet of the TR beta transcriptional process, the levels of the DIO group and the DIO-R group are lower than those in the group. The level of D1 protein and FAS expression in the liver were significantly higher than that of the DIO-R group, while the expression of M RNA and protein level and CPT1 a, PGC1 alpha and CYP7A1 in TR beta was significantly lower than that of the DIO-R group (P0.05), but there was no significant difference between the two groups. During the period (17 weeks), the expression of MI R-383, MI R-34a and MI R-146b in the liver of the group DIO was significantly higher than that in the DIO-R group, and the expression of D1, TR beta and plasma T3 were significantly lower than that in the DIO-R group. The body weight, plasma TG level and TC level were significantly higher than that in group DIO-R (P0.05). In the late stage of high fat diet (27 weeks), the MI R-383 in the liver of DIO group was significantly higher than that in the DIO-R group. The level of D1 in the liver and the level of T3 in the liver were significantly lower than that in the DIO-R group (P0.05). The expression of the liver in the three groups of mice was no more than that of the DIO-R group. The weight of the significant difference (P0.05) group.DIO, the expression of FAS, the content of TG, TC and LDL-C were significantly higher than that of the DIO-R group (P0.05). The correlation analysis showed that the level of MI R-383 and D1 protein in the liver was negatively correlated (P0.05), and there was a significant negative correlation between the liver and the level of the egg white. There was a significant negative correlation between the level of RNA and the protein level (P0.05). The content of TG and TC in the liver was significantly positively correlated with the content of TG and TC in the plasma (P0.05), MI R-146b was positively correlated with the TG and TC content in plasma, but was not significant (P0.05). 5) conclusion: the effect of high fat diet feeding on the expression of thyroid hormone metabolism related micro RNAs in the liver of DIO-R and DIO mice was different in different cycles. Compared with the DIO-R group, the expression of MI R-383 in the liver of early DIO mice was inhibited, and the expression of D1 in the liver was increased, while high fat diet was used in the middle and late stage of high fat feeding. The expression of MI R-34a and MI R-146b in the liver of the DIO group increased, making the expression of TR beta in the liver inhibited mi R-383 in the liver of the.DIO-R and DIO mice, and the difference in the expression of the lipid metabolism related genes in the target gene. The difference between obesity and obesity resistance phenotypes.
【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：R589.2

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