高脂饮食诱导下的肥胖和肥胖抵抗小鼠棕色脂肪组织非震颤性产热变化的研究

发布时间：2018-08-04 16:24

【摘要】：目的:肥胖是由于能量摄入和能量消耗的长期不平衡造成的,然而因高能量摄入却产生肥胖抵抗的现象的个体在人群和不同动物种类中都普遍存在,但其发生机制尚不明确。因此,本研究采用C57BL/6J小鼠建立高脂饮食诱导的肥胖动物模型(Diet-induced obesity,DIO)和肥胖抵抗动物模型(Diet-induced obesity resistance,DIO-R),探讨棕色脂肪组织的非颤性产热功能变化在高脂饮食诱导肥胖或肥胖抵抗中的作用及机制。方法:选取8周龄健康雄性C57BL/6J小鼠,随机分成低脂饮食组(LFD)和高脂饮食组(HFD),在自由进食和饮水条件下,低脂组小鼠喂养低脂饲料,高脂饮食组喂养高脂饮食,每周记录体重。喂养至第10周时,高脂饮食组小鼠体重显著高于低脂对照组(≥Mean+3SD)者定义为肥胖敏感小鼠;高脂饮食喂养后体重仍低于上述标准者(Mean+3SD)定义为肥胖抵抗小鼠。第11周测定各组小鼠每日进食量,每类小鼠随机分出一组进行急性冷刺激处理(4℃,6小时)后处死,收集棕色脂肪组织(Brown adipose tissue,BAT)和皮下脂肪组织(Subcutaneous adipose tissue,SAT),采用HE染色观察各组织脂肪细胞形态、脂质沉积程度;Real-time PCR检测脂肪组织目标基因表达水平(UCP1,PGC-1αand PRDM-16),免疫组织化学染色观察皮下脂肪组织UCP-1表达情况。结果:高脂喂养第10周,根据体重与低脂对照组比较结果,将高脂饮食组分为DIO鼠与DIO-R鼠。检测其连续五天进食量显示,DIO鼠与DIO-R鼠平均每日能量摄入量均显著高于对照组。对脂肪组织的HE染色后观察发现,与低脂组相比,无论是常温下还是冷刺激6小时后,DIO鼠BAT与SAT中可观察到大脂肪空泡与更大的脂肪细胞轮廓,明显大于对照组与DIO-R鼠;DIO-R鼠BAT与SAT和低脂组相比,无论是常温下还是冷刺激6小时后,都无明显差异;在BAT中,DIO鼠在常温下ucp-1的m RNA水平高于低脂组,在急性冷刺激下,ucp-1表达水平并没有发生改变,而DIO-R鼠无论是在常温下还是冷刺激下UCP-1的表达水平明显上调,且DIO-2的m RNA表达水平明显高于其他组;常温下和冷刺激下,DIO-R鼠Prdm-16的m RNA表达水平高于低脂组;在冷刺激下,对照组与DIO组都有很明显的增高,而DIR鼠并没有发生变化。在SAT中,无论常温下还是冷刺激下,DIO-R鼠的UCP-1表达水平明显高于对照组和DIO鼠;其次DIO-R鼠的PGC-1α基因m RNA表达水平与UCP-1表达相一致,无论是常温还是冷刺激下,都是明显高于对照鼠和DIO鼠;而DIO鼠中PGC-1α基因m RNA表达水平是低于正常鼠;无论是常温还是冷刺激下,DIO与DIR鼠的Prdm-16基因的m RNA表达高于对照组;常温下,DIO-R鼠DIO-2基因m RNA表达水平高于对照组和DIO鼠。其次是免疫组化结果,与DIO-R鼠皮下脂肪ucp-1的m RNA相一致,无论是冷刺激还是常温,DIO-R鼠皮下脂肪ucp-1表达明显高于其他组。结论:本研究结果提示棕色脂肪组织非颤性产热功能的增强及皮下脂肪组织“米色化”水平的提高是高脂饮食诱导肥胖抵抗小鼠保持较小体重增加的一个重要原因,具体的机制有待进一步探索。
[Abstract]:Objective: obesity is caused by the long-term imbalance of energy intake and energy consumption. However, individuals who produce obesity resistance due to high energy intake are common in both population and different animal species, but their mechanism is not clear. Therefore, this study uses C57BL /6J mice to establish high fat diet induced obese animal models. Diet-induced obesity (DIO) and obesity resistant animal model (Diet-induced obesity resistance, DIO-R), explore the role and mechanism of the change of non tremor heat producing function of brown adipose tissue in high fat diet induced obesity and obesity resistance. Methods: 8 Zhou Lingjian healthy male C57BL/6J mice were selected and randomly divided into low fat diet group (LFD) and high In the fat diet group (HFD), low fat diet group was fed low fat diet and high fat diet group was fed a high fat diet, and the weight was recorded every week in the low fat diet group. The body weight of the high fat diet group was significantly higher than that of the low fat control group (> Mean+3SD) in the high fat diet group at tenth weeks. The standard person (Mean+3SD) was defined as a obese resistance mouse. The daily intake of diet was measured in each group of mice in eleventh weeks. Each group was randomly assigned to death after acute cold stimulation (4, 6 hours), and the brown fat tissue (Brown adipose tissue, BAT) and subcutaneous fat tissue (Subcutaneous adipose tissue, SAT) were collected and observed by HE staining. The morphology of adipocyte and the degree of lipid deposition in each tissue; Real-time PCR was used to detect the expression level of target gene of adipose tissue (UCP1, PGC-1 alpha and PRDM-16). The expression of UCP-1 in subcutaneous adipose tissue was observed by immunohistochemical staining. Results: high fat feeding was used for tenth weeks, and the high fat diet group was divided into DIO mice and D groups according to the results of weight and low fat control group. The average daily intake of IO-R mice for five days showed that the average daily energy intake of both DIO and DIO-R mice was significantly higher than that in the control group. After HE staining of adipose tissue, compared with the low fat group, the large fat vacuoles and larger adipocyte silhouette could be observed in BAT and SAT in DIO rats, no matter at normal temperature or 6 hours of cold stimulation. Compared with the control group and the DIO-R rat, the BAT of the DIO-R rat was not significantly different from the SAT and low fat groups for 6 hours at normal temperature or cold stimulation. In BAT, the m RNA level of DIO rats at normal temperature was higher than that of the low fat group. The expression level of UCP-1 did not change under the acute cold stimulation, while the DIO-R rats were at normal temperature or cold stings. The expression level of UCP-1 was obviously up-regulated, and the expression level of M RNA in DIO-2 was significantly higher than that in other groups. The m RNA expression level of Prdm-16 in DIO-R rats was higher than that in low fat group under normal temperature and cold stimulation. Under cold stimulation, the control group and DIO group were significantly higher, while DIR mice did not change. In SAT, under normal temperature or cold stimulation, The expression level of UCP-1 in DIO-R rats was significantly higher than that of the control and DIO mice, and the m RNA expression level of the PGC-1 a gene in the second DIO-R mice was the same as that of the UCP-1 expression. Both the normal and the cold stimuli were significantly higher than those of the control rats and DIO mice. The expression of M RNA in the Prdm-16 gene of DIR mice was higher than that in the control group. At normal temperature, the expression level of M RNA of DIO-2 gene in DIO-R rats was higher than that of the control group and the DIO rat. The results suggest that the enhancement of the non tremor function of the brown adipose tissue and the improvement of the "Beige" level of the subcutaneous adipose tissue are an important reason for the high fat diet to induce the weight gain of the obese resistance mice, and the specific mechanism needs to be further explored.
【学位授予单位】：重庆医科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R589.2

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