高脂饮食对小鼠胃蛋白质组表达水平的影响

以高脂饮食小鼠为模型,多角度分析高脂饮食对小鼠胃蛋白组表达的影响。实验小鼠(C57BL/6)随机分配两组,实验组食用高脂饲料,对照组食用正常饲料,喂养110d后,把胃组织分为前胃、胃体和胃窦3个区分别进行蛋白质谱鉴定,随后比较两组实验的蛋白表达谱,分别筛选两组之间的差异蛋白以及胃分区的差异蛋白(差异倍数≥2),并对其进行GO富集及蛋白相互作用网络分析。对照组和实验组共鉴定到9 307种蛋白,筛选特异性肽段≥1且重复实验中至少鉴定到2次的蛋白,最后剩余4 066种蛋白,其中对照组3654种,实验组3832种。进一步从生物功能角度整体分析了胃组织的蛋白表达谱,结果发现实验组小鼠胃组织中高表达蛋白主要参与蛋白稳定和运输等生物学过程。而在对胃分区差异蛋白的功能分析表明,前胃主要参与角质化和肌动蛋白组装相关生物学过程,且受饮食影响程度较小;胃体和胃窦主要执行消化功能,高脂饮食后对胃的基本消化功能并无显著影响,但与对照组相比,参与蛋白转运和脂肪代谢相关生物学过程的蛋白显著高表达。     

二氢杨梅素对高脂饮食诱导的小鼠肥胖的影响及其机制

目的:观察二氢杨梅素(DHM)对高脂饮食诱导小鼠肥胖的影响,并探讨其作用机制是否与促进WAT棕色化有关。方法:60只c57bl/6j小鼠随机分为6组(n=10):①正常对照组(ND组):普通饲料喂养、②正常对照+低剂量DHM组(ND+L-DHM组):普通饲料喂养同时用低剂量DHM(125 mg/(kg·d))处理、③正常对照+高剂量DHM组(ND+H-DHM组):普通饲料喂养同时用高剂量DHM(250 mg/(kg·d))处理、④高脂饮食组(HFD):高脂饲料喂养、⑤高脂饮食+低剂量DHM组(HFD+L-DHM组):高脂饲料喂养同时用低剂量DHM处理、⑥高脂饮食+高剂量DHM组(HFD+H-DHM组):高脂饲料喂养同时用高剂量DHM处理。16周后小鼠空腹过夜,取血测空腹血糖和血脂,随后处死动物,测体长,算出Lee's指数;取肩胛下、腹股沟和附睾处脂肪组织称重后,甲醛固定、HE染色观察脂肪细胞大小,免疫组化检测解偶联蛋白1(UCP1)的表达;实验期间每4周测一次小鼠体重。结果:与ND组相比较,HFD组小鼠体重显著升高,提示肥胖小鼠模型复制成功。此外,HFD组小鼠体脂重量、脂肪细胞直径、Lee's指数和血糖显著增加、脂肪细胞UCP1的表达升高;使用L-DHM和H-DHM处理HFD小鼠后,体脂重量、脂肪细胞直径、Lee's指数和血糖等指标显著逆转,而脂肪细胞UCP1的表达升高更为显著;但L-DHM和H-DHM对正常小鼠上述指标无显著影响。结论:二氢杨梅素抑制高脂饮食诱导的小鼠肥胖,其机制可能与促进WAT棕色化有关。     

Hormonal status modifies renin-angiotensin system-regulating aminopeptidases and vasopressin-degrading activity in the hypothalamus-pituitary-adrenal axis of male mice

Local renin-angiotensin systems (RAS) have been postulated in brain, pituitary and adrenal glands. These local RAS have been implicated, respectively, in the central regulation of the cardiovascular system and body water balance, the secretion of pituitary hormones and the secretion of aldosterone by adrenal glands. By other hand, it is known that the hypothalamus-pituitary-adrenal (HPA) axis is involved in blood pressure regulation, and is affected by sex hormones. The aim of the present work is to analyze the influence of testosterone on RAS-regulating aminopeptidase A, B and M activities and vasopressin-degrading activity in the HPA axis, measuring these activities in their soluble and membrane-bound forms in the hypothalamus, pituitary and adrenal glands of orchidectomized males and orchidectomized males treated subcutaneously with several doses of testosterone. The present data suggest that in male mice, testosterone influences the RAS- and vasopressin-degrading activities at all levels of the HPA axis.     

Animal models of in utero exposure to a high fat diet: A review

The incidence of metabolic disease, including type 2 diabetes and obesity, has increased to epidemic levels in recent years. A growing body of evidence suggests that the intrauterine environment plays a key role in the development of metabolic disease in offspring. Among other perturbations in early life, alteration in the provision of nutrients has profound and lasting effects on the long term health and well being of offspring. Rodent and non-human primate models provide a means to understand the underlying mechanisms of this programming effect. These different models demonstrate converging effects of a maternal high fat diet on insulin and glucose metabolism, energy balance, cardiovascular function and adiposity in offspring. Furthermore, evidence suggests that the early life environment can result in epigenetic changes that set the stage for alterations in key pathways of metabolism that lead to type 2 diabetes or obesity. Identifying and understanding the causal factors responsible for this metabolic dysregulation is vital to curtailing these epidemics. This article is part of a Special Issue entitled: Modulation of Adipose Tissue in Health and Disease.     

Effects of neonatal sympathectomy on brown fat development and susceptibility to high fat diet induced obesity in mice.

Injections of 6-hydroxydopamine in mouse neonates caused extensive and long lasting damage to the sympathetic nervous system and impaired brown fat development. Brown adipose tissue (BAT) thermogenic capacity of sympathectomized mice (up to 120 days old) was reduced because of marked reductions in the tissue mitochondrial protein content and the mitochondrial concentration of uncoupling protein, as assessed by [3H]GDP binding and immunoassay. Neonatal sympathectomy did not affect BAT DNA content. Sympathectomized mice also had reduced epinephrine-stimulated rates of oxygen consumption. BAT of sympathectomized mice failed to respond by increases in [3H]GDP binding to isolated mitochondria and uncoupling protein concentration when animals were offered a palatable high-fat dietary supplement that increased calorie intake of both normal and sympathectomized mice. The high-fat diet caused increases in body weight, carcass fat, and gonadal white fat pad weights in sympathectomized animals that were similar to those of control mice. These results show that inactivation of BAT metabolism did not accentuate the development of obesity caused by a dietary supplement rich in fat and suggest that stimulation of BAT metabolism was not very effective in counteracting the obesity-inducing effect of this diet.     

Effect of stress on the acetylcholinesterase activity of the hypothalamus-pituitary-adrenal axis in the rat

Acetylcholinesterase (AchE, EC 3.1.1.7) activity was determined in cerebral cortex, hypothalamus, adenohypophysis and adrenal gland in response to acute and chronic stress. Chronic exposure of animals to cold stress (at 4 degrees C for 7 days) resulted in significant decline of AchE activity in all tissues studied. Similar results were obtained when animals were exposed to acute immobilization and cold stress (at 4 degrees C) simultaneously. In another experiment, animals were treated with 2 mg/kg of corticosterone prior to AchE determination. Corticosterone administration resulted in a significant decline in AchE activity of the cortex, the hypothalamus and the adrenal but failed to affect the adenohypophysis AchE level. Exposing adrenalectomized animals to acute stress resulted in no significant changes in the cortex and the hypothalamus but caused a significant decline in AchE of the adenohypophysis. It was concluded from this study that corticosterone might mediate the stress effect on AchE activity.     

Planar polarity: photoreceptors on a high fat diet

Differential activity of Frizzled in the R3/R4 photo-receptors of Drosophila regulates the orientation of ommatidia. New evidence suggests that the cadherins Dachsous and Fat act upstream of Frizzled in this process.     

裂殖壶藻藻油DHA对高脂饮食诱导肥胖小鼠的影响

【目的】肥胖症是一种慢性代谢类疾病,具有较高的发病率和高危后果。研究表明,n-3多不饱和脂肪酸(n-3 Polyunsaturated fatty acids,n-3 PUFAs),特别是二十二碳六烯酸(Docosahexaenoic acid,DHA)对与肥胖症相关疾病有较好的防治效果,对体内脂质代谢有重要的调节作用。探讨裂殖壶藻(Schizochytrium sp.)藻油DHA对高脂饮食诱导肥胖小鼠体重、脂肪组织重量、血脂、肝和脂肪组织病理形态和脂质代谢相关基因表达的影响。【方法】通过高脂饮食建立小鼠肥胖模型,以体重增幅15%为标准分出肥胖小鼠。试验共分五组:(1)低脂对照组;(2)高脂模型组;(3)高脂+低剂量藻油组(50 mg DHA/kg);(4)高脂+中剂量藻油组(100 mg DHA/kg);(5)高脂+高剂量藻油组(200 mg DHA/kg)。其中,藻油处理组灌服相应剂量藻油,低脂对照组和高脂模型组灌胃同等体积玉米油。处理9周后,腹腔麻醉,摘眼球取血并分离血清,测血清中甘油三酯、胆固醇和高密度脂蛋白含量;之后处死小鼠,分离附睾、肾周和肠系膜脂肪组织及肝脏,称湿重;附睾脂肪和肝组织切片进行HE染色,观察病理变化情况;利用RT-PCR检测附睾脂肪组织中激素敏感脂酶(Hormone sensitive lipase,HSL)基因的m RNA表达情况。【结果】藻油处理组小鼠体重没有显著下降,但是腹部脂肪重量显著降低、脂肪细胞体积明显小于高脂模型组;同时血清中甘油三酯、胆固醇含量显著降低,肝组织异位脂肪堆积明显减少;脂肪组织中HSL基因的表达水平显著提高。【结论】裂殖壶藻藻油DHA处理能显著降低高脂饮食导致的小鼠腹部脂肪积累并改善血脂,可能有利于肥胖症的防治。     

高脂食物对动脉硬化合并类风湿关节炎小鼠肠道菌群的影响

目的 分析高脂食物对动脉硬化合并类风湿关节炎小鼠肠道微生物的影响,了解动脉硬化合并类风湿关节炎小鼠肠道微生物的变化。方法 8周龄ApoE-/-小鼠饲喂高脂食物和普通食物至17周龄来诱发动脉硬化症状,再通过给17周龄ApoE-/-小鼠腹腔注射抗6-磷酸葡萄糖异构酶（glucose-6-phosphate isomerase,GPI）抗体呈阳性的K/BxN血清,从而诱导其产生类风湿关节炎症状。通过Illumina HiSeq平台对各组小鼠粪便进行16S rDNA V4区测序,分析动脉硬化合并类风湿关节炎小鼠肠道微生物的变化。结果 ApoE-/-小鼠饲喂高脂食物后,其血清低密度脂蛋白胆固醇（LDL-C）浓度和血清总胆固醇（TC）浓度均显著升高,主动脉内膜斑块面积比喂普通食物的ApoE-/-小鼠显著增加,表明ApoE-/-小鼠饲喂高脂食物后引起更显著的动脉硬化症状。再通过腹腔注射抗GPI抗体呈阳性的K/BxN血清,各组ApoE-/-小鼠均出现关节肿胀,饲喂高脂食物的ApoE-/-小鼠其踝关节宽度和临床评分（clinical score）低于饲喂普通食物组小鼠。OTU数、Shannon指数和Simpson指数显示高脂食物和K/BxN血清处理组ApoE-/-小鼠肠道菌群多样性降低,Firmicutes/Bacteroidetes值升高,t-test分析显示在属水平上,Prevotellaceae_UCG-001显著降低,Ruminiclostridium_6显著升高。t-test分析和Firmicutes/Bacteroidetes比值显示ApoE-/-小鼠肠道菌群结构紊乱。结论 高脂食物使ApoE-/-小鼠的肠道菌群组成和结构发生改变,导致ApoE-/-小鼠的动脉硬化症状加重,类风湿关节炎症状减轻。提示肠道微生物组成和结构的改变,可能与动脉硬化合并类风湿关节炎发病机制相关。     

Electrical activity of the amygdala and the septum of rats on a high fat or a high protein diet

The authors studied biopotentials in the region of the amygdala and the septum of rats fed on a standard, high protein or high fat diet. During the first 3-6 days after changing from the standard to the high protein or high fat diet, a decrease in the amplitude of electrical activity was found in both the regions in question. After 3 days on the high fat or the high protein diet, an increase was found in the frequency of electrical activity in the amygdala or the septum, according to the type of diet. A study of the amplitude of electrical activity showed that the electrical potential in the septum was always lower than in the amygdala. The frequency spectrum analysis showed a marked change in the superimposed frequency curve only in animals fed on the high fat diet.     

Activation of inflammasomes in podocyte injury of mice on the high fat diet: Effects of ASC gene deletion and silencing

Inflammasome, an intracellular inflammatory machinery, has been reported to be involved in a variety of chronic degenerative diseases such as atherosclerosis, autoinflammatory diseases and Alzheimer's disease. The present study hypothesized that the formation and activation of inflammasomes associated with apoptosis associated speck-like protein (ASC) are an important initiating mechanism resulting in obesity-associated podocyte injury and consequent glomerular sclerosis. To test this hypothesis, Asc gene knockout (Asc^−/−), wild type (Asc^+/+) and intrarenal Asc shRNA-transfected wild type (Asc shRNA) mice were fed a high fat diet (HFD) or normal diet (ND) for 12 weeks to produce obesity and associated glomerular injury. Western blot and RT-PCR analyses demonstrated that renal tissue Asc expression was lacking in Asc^−/− mice or substantially reduced in Asc shRNA transfected mice compared to Asc^+/+ mice. Confocal microscopic and co-immunoprecipitation analysis showed that the HFD enhanced the formation of inflammasome associated with Asc in podocytes as shown by colocalization of Asc with Nod-like receptor protein 3 (Nalp3). This inflammasome complex aggregation was not observed in Asc^−/− and local Asc shRNA-transfected mice. The caspase-1 activity, IL-1β production and glomerular damage index (GDI) were also significantly attenuated in Asc^−/− and Asc shRNA-transfected mice fed the HFD. This decreased GDI in Asc^−/− and Asc shRNA transfected mice on the HFD was accompanied by attenuated proteinuria, albuminuria, foot process effacement of podocytes and loss of podocyte slit diaphragm molecules. In conclusion, activation and formation of inflammasomes in podocytes are importantly implicated in the development of obesity-associated glomerular injury.     

Effects of a high fat diet on thyroid activity,with special reference to thyroidal responses to cold

Male rats of Wistar strain were fed a standard diet (14% calories as fat or a high fait diet (80% calories as fat) for 4 to 5 weeks at 20°C. A high fat diet caused a marked hypertrophy of brown and white adipose tissue, but no change in the weight of thyroid, while there was a significant decrease in the thyroid activity as indicated by low T/S ratio. Also, the 48-hr conversion ratio of¹³¹I to protein-bound¹³¹I (PB¹³¹I) was lower. However, plasma PB¹³¹I level in this group was not different from that in the control group of rats. At 20°C plasma PB¹³¹I levels were progressively decreased over a period of 48 hours in the control group, while in the high fat diet group the initial level was maintained throughout the period. In the control group cold exposure at 3° to 5°C caused a significant elevation of PB¹³¹I level, but later it decreased to the level at 20°C. In the high fat diet group the plasma PB¹³¹I was not influenced by the same cold exposure. Fractional turnover rate of¹³¹I-thyroxine was similar in the two groups. It increased significantly on exposure to cold in the control group, while it remained unchanged in the high fat diet one. These results suggest that a high fat diet has some depressive influence on thyroidal activity and the responses to cold.

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Zusammenfassung Männliche Wistar Ratten lebten 4–5 Wochen bei 20°C und Standardfutter mit 14% Kalorien in Fett oder einem fettreichen Futter (80% Kalorien in Fett). Das fettreiche.Futter bewirkte eine starke Zunahme des braunen und weissen Fettgewebes ohne Änderung des Schilddrüsengewichtes, während die Schilddrüsenaktivität stark abfiel, erkennbar an dem niedrigen T/S Quotienten. Ebenso war die 24-Stunden Umwandlung von¹³¹I in proteingebundenes¹³¹I (PB¹³¹I) niedriger als bei den Kontroll-Tieren, jedoch war der Plasma PB¹³¹I-Spiegel der beiden Gruppen gleich. Bei 20°C fiel der PB¹³¹I-Spiegel der Kontroll-Tiere innerhalb 48 Stunden langsam ab, während er bei den fettreich gefütterten Tieren gleich blieb. In der Kontrollgruppe bewirkte 3°–5°C Kälteexponierung eine signifikante Erhöhung des PB¹³¹I Spiegels mit langsamen Abfall auf die Werte bei 20°C, während der Spiegel bei den fettreich gehaltenen Tieren unverändert blieb. Die fraktionierte Umsatzrate von¹³¹I-Thyroxin war in beiden Gruppen gleich.Sie stieg bei Kälteexponierung in der Kontrollgruppe signifikant an und blieb bei den fettreich gefütterten Tieren unverändert. Danach übt fettreiches Futter eine hemmende Wirkung auf die SD-Aktivität und Reaktionen auf Kälte aus.

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Resume On a élevé des rats mâles de la race Wistar à 20°C durant 4 à 5 semaines. Les uns recevaient une alimentation normale (14% des calories provenaient de graisses), les autres une alimentation très grasse (80% des calories étaient constitués par des corps gras). L'alimentation riche en graisses a eu pour effet une forte augmentation des tissues adipeux bruns et blancs, mais pas de modification du poids de la glande thyroïde. L'activité de celle-ci fut pourtant ralentie ce qui s'est traduit par une baisse du quotient T/S. La transformation en 24 heures de¹³¹I en iode proteïnique¹³¹I (PB¹³¹I) fut également inférieure que dans le cas des bêtes de contrôle. Pourtant, le taux de PB¹³¹I est resté le même dans le plasma des deux groupes. A 20°C, le taux de PB¹³¹I diminue lentement en 48 heures chez les bêtes de contrôle alors qu'il est resté le même chez les animaux soumis à un régime gras. Une exposition au froid (3° à 5°C) du groupe de contrôle y a provoqué une hausse significative du taux de PB¹³¹I, mais celuici redescendit au niveau antérieur, celui correspondant à 20°C. Dans le cas des rats soumis à un régime gras, on n'a pas constaté d'influence semblable lors de leur exposition au froid. Le taux fractionné de transformation de la thyroxine¹³¹I a réagi de même dans les deux groupes: Il y a ici aussi hausse significative dans le groupe de contrôle, mais pas dans celui soumis à un régime gras. Ces résultats laissent supposer, qu'un régime riche en graisses agit comme inhibiteur sur l'activité thyroïdienne et sur les réactions au froid.

     

Effect of non-digestible gluco-oligosaccharides on glucose sensitivity in high fat diet fed mice

Non digestible dietary carbohydrates have been reported to modify lipaemia and post-prandial glycaemia and insulinaemia. The aim of this study was to investigate the effect of a non-digestible gluco-oligosaccharides (GOS) diet on glucose, insulin, triglycerides and free fatty acid blood levels and glucose sensitivity in high fat diet fed mice (a high fat diet composed of 45% fat, 35% carbohydrate and 20% protein). Female C57B16/J mice were divided into two groups fed a high fat diet (HF) for 20 weeks supplemented or not with 1.5 g/kg/day of GOS (HF-GOS). The GOS supplementation did not change body weight nor fat pad mass, nor any of the blood parameters measured (glucose, insulin, leptin, triglycerides, and free fatty acids). However, mice which received the GOS supplemented diet showed an increased glucose utilization after a 1 g/kg load of glucose compared with the mice fed the high fat diet alone. Our results suggest a role for non-digestible GOS in the regulation of carbohydrate metabolism.     

Pioglitazone retrieves hepatic antioxidant DNA repair in a mice model of high fat diet

Background  

Pioglitazone was reported to improve hepatic steatosis and necroinflammation in human studies. To investigate whether the hepato-protective effect of pioglitazone was associated with an improvement of antioxidant defense mechanism, oxidative DNA damage and repair activity were determined in a high fat diet model. Male C57BL/6 mice were respectively fed with a 30% fat diet, the same diet with pioglitazone 100 mg/kg/day, or a chow diet as control for 8 weeks. Tissue oxidative stress was indicated by malondialdehyde concentration. Oxidative DNA damage was detected by immunohistochemical 8-oxoG staining. Enzymatic antioxidant defense was detected by the real-time PCR of superoxide dismutase (Sod1, Sod2) and DNA glycosylase (Ogg1, MutY). Oxidative DNA repair was detected by immunohistochemical staining and western blotting of OGG1 expression.     

Phylometabonomic patterns of adaptation to high fat diet feeding in inbred mice

Insulin resistance plays a central role in type 2 diabetes and obesity, which develop as a consequence of genetic and environmental factors. Dietary changes including high fat diet (HFD) feeding promotes insulin resistance in rodent models which present useful systems for studying interactions between genetic background and environmental influences contributing to disease susceptibility and progression. We applied a combination of classical physiological, biochemical and hormonal studies and plasma (1)H NMR spectroscopy-based metabonomics to characterize the phenotypic and metabotypic consequences of HFD (40%) feeding in inbred mouse strains (C57BL/6, 129S6, BALB/c, DBA/2, C3H) frequently used in genetic studies. We showed the wide range of phenotypic and metabonomic adaptations to HFD across the five strains and the increased nutrigenomic predisposition of 129S6 and C57BL/6 to insulin resistance and obesity relative to the other strains. In contrast mice of the BALB/c and DBA/2 strains showed relative resistance to HFD-induced glucose intolerance and obesity. Hierarchical metabonomic clustering derived from (1)H NMR spectral data of the strains provided a phylometabonomic classification of strain-specific metabolic features and differential responses to HFD which closely match SNP-based phylogenetic relationships between strains. Our results support the concept of genomic clustering of functionally related genes and provide important information for defining biological markers predicting spontaneous susceptibility to insulin resistance and pathological adaptations to fat feeding.     

高脂饮食对小鼠附睾内质网应激的影响及褪黑素的干预作用

目的探讨内质网应激在高脂饮食引起的ApoE基因敲除小鼠附睾损伤中的作用及褪黑素（MT）的干预机制。方法将12只ApoE基因敲除的C57BL／6J雄性小鼠随机分为高脂饮食组及MT处理组。高脂饮食组为ApoE基因敲除小鼠,给予高脂饮食;MT处理组给予高脂饲养外,并MT灌胃。以6只野生型C57BL／6J雄性小鼠作为对照组,给予普通饮食。饲养12w后,取附睾组织制片,HE染色观察附睾的病理学形态,免疫组化检测GRP78和CHOP的表达。结果HE染色显示,高脂饮食组小鼠,附睾上皮细胞形态结构不清,细胞萎缩。对照组和褪黑素处理组小鼠附睾上皮细胞形态结构完整,细胞排列整齐。免疫组化显示高脂饮食组小鼠附睾中GRP78、CHOP表达增强（P〈0．01）。MT处理组和高脂饮食组相比,附睾中GRP78、CHOP表达下调（P〈0．01）。结论内质网应激参与高脂饮食导致的附睾损伤;MT可能通过抑制附睾内质网应激,减轻高脂饮食对小鼠附睾的损伤。