Ageing is associated with brown adipose tissue remodelling and loss of white fat browning in female C57BL/6 mice

Fat storage changes throughout life and affects body metabolism. Ageing impact on brown (BAT) and white adipose tissue (WAT) deserves attention, especially in females, because they are less prone to age‐induced weight gain. While in male mice the impact of ageing on adipose tissue remodelling is well characterized, the effects in female mice remain largely unclear. Thus, we investigated BAT and WAT remodelling during ageing in female C57BL/6 mice. At 3 months, body weight was 24 ± 0.3 g (mean±SD), and it increased from 6 to 9 months of age (+20%, P < 0.0001). Oral glucose tolerance test showed no disturbance of glucose metabolism. All WAT depots became heavier, and white adipocytes hypertrophied. The subcutaneous and visceral WAT had clusters of beige cells in younger mice, but they were progressively lost by ageing, indicating loss of WAT browning. Older mice had hypertrophied classic brown adipocytes that had larger cytoplasmic lipid droplets than younger mice. Pearson's correlation showed that WAT mass has a weak correlate with BAT mass, although white adipocyte diameter has a strong correlation with classic brown adipocyte size. In conclusion, our results indicate that female C57BL/6 mice have a progressive age‐dependent loss of subcutaneous and visceral WAT browning, and this process runs in parallel with BAT morphological changes towards a fat storer phenotype, independent of cycling or disturbances in glucose metabolism.     

Chronic lathyrism. Protective effect of pyridinol carbamate on connective tissue lesions in the rat (author's transl)]

The use of lathyric toxins (BAPN) in low dosage (1 g/kg/day) for a period of 8 weeks caused in the rat simultaneous changes in the skin and aortic connective tissues. In the skin. collagen tissue was dislocated and broken in fragments, the elastic tissue disappeared, the fibroblasts were vacuolized and presented evidence of injury. These lesions were comparable to those observed in human skin during ageing. The addition of pyridinol carbamate (PDC) to BAPN prevents the formation of lesions of the elastic tissue and of fibroblasts. When given after the cessation of the lathyrogen treatment PDC arrested the formation of the lesions and accelerated their regression.     

Comparison of the N- and O-linked glycopeptides of lymph node cells from C57 BL/6 lpr/lpr and C57 BL/6 mice.

We have tested the hypothesis that some phenotypic characteristics of the lymphocytes from mice with lymphoproliferative disease (lpr) could be explained by abnormal glycosylation of membrane proteins. Lymph node cells from normal C57 BL/6 and from C57 BL/lpr mice were labelled with tritiated sugars. Membrane proteins were released with trypsin, then with pronase. After complete pronase digestion, glycopeptides were first separated on Bio Gel P-6 and then on Con A-Sepharose. Fractions not binding to Con A (Con A negative) were also separated on Lens culinaris agglutinin-Sepharose. Marked differences between normal and lpr cells were noticed. First, there were more glucosamine-labelled peptides with very high molecular weight (eluting fast on Bio Gel P-6) on lpr cells than on normal lymphocytes. Second, the proportion of mannose-labelled peptides binding to Con A was smaller in the lpr cells. Third, among the Con A negative peptides, the proportion binding to Lens culinaris agglutinin was higher in lpr cells. Thus, lpr cells seem to carry more alpha 1-6 fucosylated chains and larger size carbohydrates. These alterations were also confirmed by gel electrophoresis of lectin-selected iodinated cell surface antigens and seem to be restricted to a very limited number of peptides. Thus, there may be primary changes in glycosylation in lpr cells. Alternatively, the glycosylation pattern of lpr cells may be characteristic for a subpopulation of T-lymphocytes that is expanded in this disease, or for a certain stage of activation. A large proportion of Con A-negative, Lens culinaris-positive peptides is a rather unusual feature in murine cells and requires further investigation.     

Evolution of the adipose tissue during the postembryonic development in Coleoptera Catopidae. I. Studies in Choleva fagniezi and Speophyes lucidulus (author's transl)]

Cytological studies of the fat body have been performed during the postembryonic development of 2 Coleoptera Catopidae: Choleva fagniezi and Speophyes lucidulus. As in other insects, the cells store large amounts of glycogen, lipids and proteins during the larval life; these reserves would be lysed and used during the metamorphosis. According to the species, protein globules are constituted at different larval life periods. In Choleva fagniezi they appear during the 3rd and last larval instar. In Speophyes lucidulus, protein globules appear during the 10 first days of the 1st larval instar. In the prenymphs of the 2 species, the protein globules become rich in RNA.     

硫辛酸改善高脂小鼠氧化应激和慢性炎症的研究

目的:探讨由长期喂饲高脂引发的小鼠机体氧化应激对细胞因子的分泌以及炎症相关基因表达的影响,评价通过添加抗氧化剂硫辛酸对长期氧化应激和慢性炎症的改善作用。方法:30只C57BL/6雄性小鼠,随机分为3组:对照组,高脂模型组(HFD),硫辛酸组(LA)。喂饲10周后测定血浆和脾脏的氧化应激指标。酶联免疫法检测血浆中IFN-γ、IL-4、IL-6、TNF-α、IL-10的含量。荧光定量PCR检测脾脏炎症相关基因C-Jun、NF-κB以及与抗氧化相关基因Mt-1的表达。结果:长期高脂喂饲可导致小鼠免疫器官抗氧化酶活性显著降低,MDA含量显著升高,形成氧化应激。机体长期处于氧化应激态可使血浆IL-4和IL-10显著降低,IFN-γ、IL-6和TNF-α水平显著升高,同时C-Jun和NF-κB炎症反应相关基因表达上调、Mt-1的表达水平下调。添加0.1%LA可有效地防止机体氧化应激的形成。结论:长期高脂喂饲导致的氧化应激可影响机体的免疫功能并诱发慢性炎症反应,LA通过直接清除自由基、恢复氧化还原平衡解除慢性氧化应激从而保护小鼠的免疫功能免受损伤。     

Effects of different fatty acids and dietary lipids on adiponectin gene expression in 3T3-L1 cells and C57BL/6J mice adipose tissue

Obesity is positively correlated to dietary lipid intake, and the type of lipid may play a causal role in the development of obesity-related pathologies. A major protein secreted by adipose tissue is adiponectin, which has antiatherogenic and antidiabetic properties. The aim of this study was to evaluate the effects of four different high-fat diets (enriched with soybean oil, fish oil, coconut oil, or lard) on adiponectin gene expression and secretion by the white adipose tissue (WAT) of mice fed on a selected diet for either 2 (acute treatment) or 60 days (chronic treatment). Additionally, 3T3-L1 adipocytes were treated for 48 h with six different fatty acids: palmitic, linoleic, eicosapentaenoic (EPA), docosahexaenoic (DHA), lauric, or oleic acid. Serum adiponectin concentration was reduced in the soybean-, coconut-, and lard-enriched diets in both groups. Adiponectin gene expression was lower in retroperitoneal WAT after acute treatment with all diets. The same reduction in levels of adiponectin gene expression was observed in epididymal adipose tissue of animals chronically fed soybean and coconut diets and in 3T3-L1 cells treated with palmitic, linoleic, EPA, and DHA acids. These results indicate that the intake of certain fatty acids may affect serum adiponectin levels in mice and adiponectin gene expression in mouse WAT and 3T3-L1 adipocytes. The effects appear to be time dependent and depot specific. It is postulated that the downregulation of adiponectin expression by dietary enrichment with soybean oil or coconut oil may contribute to the development of insulin resistance and atherosclerosis.     

Experimental investigations on estimation of myocardium and adipose tissue composition of human heart. A critical review (author's transl)]

Only quantitative assessment of the active mass of heart muscle gives correct information about the functional capacity of the human heart and is essential for discussion of pathological conditions.Removal of adipose tissue from the heart, a method created by Müller, does not yield correct results because complete separation of adipose tissue from the fibres of the myocardium is difficult.Masshoff and Scheidt have produced a method which allows estimation of active parenchyma of the human heart without removing adipose tissue. This method is based on the physical principle for binary mixtures expressing that qualities of bicomponent mixtures can be derived from the qualities of the individual components by consideration of different quantitiesUsing this method myocardium is considered as a mixture of two solid masses, namely myocardium and adipose tissue. According to Masshoff and Scheidt values of constant densities are used which represent mean values out of a large number of single values.Thus, this method is exclusively based on the assessment of weight and density of total heart by the use of a pyknometer.The following experiments were carried out for the purpose of checking this method with regard to its reliability.     

The C57BL/6 nu/nu lpr/lpr mouse. II. Pedigree and preliminary characteristics

A short-cut procedure is described which allows to construct new mouse strains which are double congenic for the nu gene (nude, athymic) and the lpr gene (lymphoproliferation). Since both nu and lpr genes are recessive and that the lack of thymus impairs the expression of the lpr phenotype in euthymic animals, the homozygosity of nude animals for the lpr gene was based on the results of progeny analyses. A C57BL/6 nu/nu lpr/lpr (B6 nu/nu, lpr/lpr) was made in four generations starting from C57BL/6 nu/nu (B6 nu/nu) and C57BL/6 lpr/lpr (B6 lpr/lpr). This possibility stems from an absence of close linkage of the nu and lpr genes. The emergence of the nude phenotype at the different steps of the pedigree was less frequent than expected if the nu and lpr genes were completely independent. However, this is probably due to environmental factors causing a negative selection of nude littermates. The B6 nu/nu lpr/lpr represents a new important tool for the study of how the thymus modulates the lpr gene controlled acceleration of autoimmunity. Preliminary data indicate that the lpr phenotype (massive lymphadenopathy and splenomegaly accompanied by severe auto-immune disease with features of systemic lupus erythematosus) appears when a thymus is grafted to the B6 nu/nu lpr/lpr.     

Responses of sympathetic nerves innervating blood vessels in interscapular, brown adipose tissue and skin during cold stimulation in anesthetized C57BL/6J mice.

The effect of cold stimulation on the activity of sympathetic nerves running along blood vessels in interscapular, brown adipose tissues (IBAT) and skin overlying IBAT was examined in 15, urethane-anesthetized, artificially ventilated, C57BL/6J mice. Cold stimulation was applied caudal to the pelvic area using a plastic bag containing iced water. The stimulation of 14-16 min duration reduced core temperature measured at the esophagus or muscle near the esophagus by approximately 4 degrees C from a control temperature of about 38 degrees C. The stimulation decreased the activity of the nerve branches to IBAT, while it increased the activity of the nerve branches to skin. Blood flow in the IBAT increased significantly following the stimulation; however, this effect was abolished by the denervation. These findings suggest that the sympathetic innervation of the blood vessels in the IBAT plays a major role in thermoregulation against cold by decreasing the vascular tone and thus increasing the IBAT blood flow. An increase in the IBAT blood flow would facilitate the dissipation of heat from the IBAT to various organs as well as the supply of energy stuffs to the IBAT.