RESUMO
SUMMARY: Adipose tissue morphology of different fat tissue depots can be described using the number of adipocytes and cell surface of adipocytes. This study deals with characteristics and morphometric analysis of white and brown adipose tissue depots in healthy adult laboratory mice, hamsters and rats of both sexes. The number of unilocular adipocytes in white adipose tissue differs from one adipose tissue depot to another, with the largest number of adipocytes in mice and a similar number in hamsters and rats. The smallest surface area and the largest percentage of small unilocular adipocytes were found in mice. White adipose tissue in hamsters and rats was predominantly made out of a larger percentage of medium-sized adipocytes and a smaller percentage of small and medium-sized adipocytes. Uncoupling protein 1 positive multilocular adipocytes were found in classic brown adipose tissue depots with larger percentages in mice (93.20 %) and hamsters (91.30 %), while rats had a smaller percentage (78.10 %). In white and brown adipose tissue, significant differences between species and both sexes within the same species were found, indicating the influence of sexual dimorphism. The presented morphometric results could serve as a basis for further studies concerning experimental animal models of metabolic disorders and obesity.
RESUMEN: La morfología del tejido adiposo de diferentes depósitos de tejido graso se puede describir utilizando el número de adipocitos y la superficie celular de los adipocitos. Este estudio analiza las características y el análisis morfométrico de los depósitos de tejido adiposo blanco y marrón en ratones, hamsters y ratas de laboratorio, adultos sanos de ambos sexos. El número de adipocitos uniloculares en el tejido adiposo blanco difiere de un depósito de tejido adiposo a otro, con el mayor número de adipocitos en ratones y un número similar en hámsteres y ratas. La superficie más pequeña y el mayor porcentaje de adipocitos uniloculares pequeños se encontraron en ratones. El tejido adiposo blanco en hámsteres y ratas estaba compuesto predominantemente por un mayor porcentaje de adipocitos de tamaño mediano y un porcentaje menor de adipocitos de tamaño pequeño y mediano. Los adipocitos multiloculares positivos para la proteína desacopladora 1 se encontraron en depósitos de tejido adiposo marrón clásico con mayores porcentajes en ratones (93,20 %) y hámsters (91,30 %), mientras que las ratas tenían un porcentaje menor (78,10 %). En el tejido adiposo blanco y pardo se encontraron diferencias significativas entre especies y entre ambos sexos dentro de una misma especie, lo que indica la influencia del dimorfismo sexual. Los resultados morfométricos presentados podrían servir como base para futuros estudios sobre modelos animales experimentales de trastornos metabólicos y obesidad.
Assuntos
Animais , Masculino , Feminino , Camundongos , Ratos , Tecido Adiposo Marrom/anatomia & histologia , Gordura Subcutânea/anatomia & histologia , Tecido Adiposo Branco/anatomia & histologia , Vísceras/anatomia & histologia , Cricetinae , Caracteres Sexuais , Modelos AnimaisRESUMO
Caloric restriction (CR) is the most effective intervention known to enhance lifespan, but its effect on the skin is poorly understood. Here, we show that CR mice display fur coat remodeling associated with an expansion of the hair follicle stem cell (HFSC) pool. We also find that the dermal adipocyte depot (dWAT) is underdeveloped in CR animals. The dermal/vennule annulus vasculature is enlarged, and a vascular endothelial growth factor (VEGF) switch and metabolic reprogramming in both the dermis and the epidermis are observed. When the fur coat is removed, CR mice display increased energy expenditure associated with lean weight loss and locomotion impairment. Our findings indicate that CR promotes extensive skin and fur remodeling. These changes are necessary for thermal homeostasis and metabolic fitness under conditions of limited energy intake, suggesting a potential adaptive mechanism.
Assuntos
Restrição Calórica , Pele/anatomia & histologia , Pele/metabolismo , Tecido Adiposo Branco/anatomia & histologia , Animais , Regulação da Temperatura Corporal , Peso Corporal , Derme/anatomia & histologia , Epiderme/anatomia & histologia , Folículo Piloso/citologia , Folículo Piloso/crescimento & desenvolvimento , Locomoção , Camundongos , Oxirredução , Pele/irrigação sanguínea , Pele/ultraestrutura , Células-Tronco/citologia , Fatores de TempoRESUMO
Previous studies have proposed a role for neuromedin B (NB), a bombesin-like peptide, in the control of body weight homeostasis. However, the nature of this role is unclear. The actions of NB are mediated preferentially by NB-preferring receptors (NBRs). Here we examined the consequences of targeted deletion of NBRs in female mice on body weight homeostasis in mice fed a normolipid diet (ND) or a high-fat diet (HFD) for 13 weeks. Body weight and food ingestion of neuromedin B receptor knockout (NBR-KO) mice fed a normolipid diet showed no difference in relation to wild-type (WT). However, the high-fat diet induced an 8.9- and 4.8-fold increase in body weight of WT and NBR-KO, respectively, compared to their controls maintained with a normolipid diet, even though the mice ingested the same amount of calories, regardless of genotype. Comparing mice fed the high-fat diet, NBR-KO mice accumulated approximately 45% less fat depot mass than WT, exhibited a lower percentage of fat in their carcasses (19.2 vs. 31.3%), and their adipocytes were less hypertrophied. Serum leptin and leptin mRNA in inguinal and perigonadal fat were lower in HFD NBR-KO than HFD WT, and serum adiponectin was similar among HFD groups and unaltered in comparison to ND-fed mice. HFD-fed WT mice developed glucose intolerance but not the HFD-fed NBR-KO mice, although they had similar glycaemia and insulinaemia. NBR-KO and WT mice on the normolipid diet showed no differences in any parameters, except for a trend to lower insulin levels. Therefore, disruption of the neuromedin B receptor pathway did not change body weight homeostasis in female mice fed a normolipid diet; however, it did result in partial resistance to diet-induced obesity.
Assuntos
Dieta , Obesidade/genética , Receptores da Bombesina/fisiologia , Tecido Adiposo Branco/anatomia & histologia , Animais , Compostos Azo , Composição Corporal/genética , Composição Corporal/fisiologia , Peso Corporal/genética , Peso Corporal/fisiologia , Corantes , Gorduras na Dieta/farmacologia , Ingestão de Energia , Metabolismo Energético/genética , Metabolismo Energético/fisiologia , Feminino , Teste de Tolerância a Glucose , Homeostase/genética , Homeostase/fisiologia , Hormônios/sangue , Leptina/biossíntese , Leptina/genética , Lipídeos/sangue , Fígado/química , Fígado/metabolismo , Camundongos , Camundongos Knockout , Receptores da Bombesina/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/genética , Transdução de Sinais/fisiologiaRESUMO
Insulin signalling in the hypothalamus plays a role in maintaining body weight. The forkhead transcription factor Foxo1 is an important mediator of insulin signalling in the hypothalamus. Foxo1 stimulates the transcription of the orexigenic neuropeptide Y and Agouti-related protein through the phosphatidylinositol-3-kinase/Akt signalling pathway, but the role of hypothalamic Foxo1 in insulin resistance and obesity remains unclear. Here, we identify that a high-fat diet impaired insulin-induced hypothalamic Foxo1 phosphorylation and degradation, increasing the nuclear Foxo1 activity and hyperphagic response in rats. Thus, we investigated the effects of the intracerebroventricular (i.c.v.) microinfusion of Foxo1-antisense oligonucleotide (Foxo1-ASO) and evaluated the food consumption and weight gain in normal and diet-induced obese (DIO) rats. Three days of Foxo1-ASO microinfusion reduced the hypothalamic Foxo1 expression by about 85%. i.c.v. infusion of Foxo1-ASO reduced the cumulative food intake (21%), body weight change (28%), epididymal fat pad weight (22%) and fasting serum insulin levels (19%) and increased the insulin sensitivity (34%) in DIO but not in control animals. Collectively, these data showed that the Foxo1-ASO treatment blocked the orexigenic effects of Foxo1 and prevented the hyperphagic response in obese rats. Thus, pharmacological manipulation of Foxo1 may be used to prevent or treat obesity.
Assuntos
Ingestão de Alimentos/efeitos dos fármacos , Fatores de Transcrição Forkhead/metabolismo , Expressão Gênica/efeitos dos fármacos , Hipotálamo/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Obesidade/tratamento farmacológico , Oligonucleotídeos Antissenso/farmacologia , Tecido Adiposo Branco/anatomia & histologia , Tecido Adiposo Branco/efeitos dos fármacos , Animais , Glicemia/metabolismo , Peso Corporal/efeitos dos fármacos , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Dieta , Ingestão de Energia/efeitos dos fármacos , Epididimo/anatomia & histologia , Epididimo/efeitos dos fármacos , Fatores de Transcrição Forkhead/genética , Hipotálamo/efeitos dos fármacos , Insulina/administração & dosagem , Insulina/sangue , Insulina/farmacologia , Proteínas Substratos do Receptor de Insulina/metabolismo , Masculino , Proteínas do Tecido Nervoso/genética , Obesidade/sangue , Obesidade/patologia , Oligonucleotídeos Antissenso/administração & dosagem , Oligonucleotídeos Antissenso/genética , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Ratos Wistar , Receptor de Insulina/metabolismo , Fatores de Transcrição de p300-CBP/metabolismoRESUMO
White adipose tissue (WAT) is the source of pro- and anti-inflammatory cytokines and recently, it has been recognized as an important source of interleukin 10 (IL-10). Acute physical exercise is known to induce an anti-inflammatory cytokine profile, however, the effect of chronic physical exercise on the production of IL-10 by WAT has never been examined. We assessed IL-10 and TNF-alpha concentration in WAT of rats engaged in endurance training. Animals were randomly assigned to either a sedentary control group (S, n=7) or an endurance trained group (T, n=8). Trained rats ran on a treadmill 5 days/wk for 8 wk (55-65% VO(2max)). Detection of IL-10 and TNF-alpha protein and mRNA expression, as well as the gene expression of PPAR-gamma, and immunocytochemistry to detect mononuclear phagocytes were carried out. A reduction in absolute retroperitoneal adipose tissue (RPAT) weight in T (44%; p<0.01), when compared with S was observed. IL-10 concentration was increased (1.5-fold, p<0.05), to a higher extent than that of TNF-alpha (66%, p<0.05) in the mesenteric adipose tissue (MEAT) of the trained group, while no change related to training was observed in RPAT. In MEAT, IL-10/TNF-alpha ratio was increased in T, when compared with S (30%; p<0.05). PPAR-gamma gene expression was increased in T (1.1-fold; p<0.01), when compared with S in the same adipose depot. No monocyte infiltration was found. In conclusion, exercise training induced increased IL-10 expression in the mesenteric depot, resulting in a modified IL-10/TNF-alpha ratio. We also conclude that WAT presents a depot-specific response to endurance training regarding the studied aspects.