RESUMO
The mouse N. alstoni spontaneously develops the condition of obesity in captivity when fed regular chow. We aim to study the differences in metabolic performance and thermoregulation between adult lean and obese male mice. The experimental approach included indirect calorimetry using metabolic cages for VO2 intake and VCO2 production. In contrast, the body temperature was measured and analyzed using intraperitoneal data loggers. It was correlated with the relative presence of UCP1 protein and its gene expression from interscapular adipose tissue (iBAT). We also explored in this tissue the relative presence of Tyrosine Hydroxylase (TH) protein, the rate-limiting enzyme for catecholamine biosynthesis present in iBAT. Results indicate that obese mice show a daily rhythm persists in estimated parameters but with differences in amplitude and profile. Obese mice presented lower body temperature, and a low caloric expenditure, together with lower VO2 intake and VCO2 than lean mice. Also, obese mice present a reduced thermoregulatory response after a cold pulse. Results are correlated with a low relative presence of TH and UCP1 protein. However, qPCR analysis of Ucp1 presents an increase in gene expression in iBAT. Histology showed a reduced amount of brown adipocytes in BAT. The aforementioned indicates that the daily rhythm in aerobic metabolism, thermoregulation, and body temperature control have reduced amplitude in obese mice Neotomodon alstoni.
RESUMO
Obesity is a growing problem worldwide with a clear impact on health status. It is also a condition that negatively affects circadian rhythms. When the mouse Neotomodon alstoni is fed a regular rodent chow, some individuals develop obesity, representing an opportunity to compare the effects of spontaneous obesity upon the circadian organization in this species with that observed in other rodents with induced obesity. We report differences in the free running circadian locomotor activity rhythm and in the effects of light pulses between lean and obese mice. Also, the photo-induced expression of the c-Fos protein and vasoactive intestinal peptide (VIP) in the suprachiasmatic nucleus (SCN) were examined at circadian time (CT) 14 and 22. We show that obese mice have a larger dispersion of the period of circadian locomotor rhythm in constant darkness. Photic induced phase shifts are nearly 50% shorter at CT 14, and 50% larger at CT 22 than in lean mice. The photoinduction of VIP in the SCN at CT 22 was larger in obese mice, which may be related to the differences observed in photic phase shifting. Our work indicates that the obesity in Neotomodon has effects on the neural mechanisms that regulate the circadian system.
RESUMO
Introducción: el desarrollo científico y tecnológico en las ciencias biológicas y biomédicas ha sido posible gracias a la utilización de modelos animales experimentales. La anemia por deficiencia de hierro (Fe), afecta aproximadamente a la tercera parte de la población mundial. La rata recién destetada ha sido el modelo animal más empleado en la obtención de un biomodelo experimental de anemia. Para la obtención de anemia se utiliza el método de depleción de la hemoglobina (Hb), mediante una alimentación basada en una dieta deficiente en Fe. Objetivo: el objetivo de este trabajo fue evaluar la eficacia de una dieta purificada a partir de caseína en la obtención de ratas anémicas. Métodos: se utilizaron 40 ratas Sprague Dawley recién destetadas (21-24 días), la mitad de cada sexo. Se alojaron en grupos de 3 del mismo sexo en cajas de acero inoxidable con piso de rejillas. Durante 8 semanas se les administró agua desionizada y una dieta de caseína al 12,58 por ciento de proteínas y 1,28 mgFe/Kg. Cada dos semanas se midió el peso corporal y a partir de la cuarta semana, la concentración de Hb. Resultados: se obtuvo un incremento significativo del peso corporal sin observarse diferencias entre hembras y machos. Se tomó como criterio de obtención de la anemia aquellos animales cuya Hb disminuyó al menos en un 30 por ciento del valor inicial promedio por grupo. El porcentaje de animales anémicos a las 8 semanas fue superior en las hembras (75 por ciento), mientras que en machos (60 por ciento). La dieta utilizada en este estudio permitió obtener ratas anémicas en el sexo hembras con una eficiencia aceptable, en relación al porcentaje de animales anémicos y al incremento del peso corporal. Conclusiones: la dieta utilizada en este estudio permitió obtener ratas anémicas en el sexo hembras con una eficiencia aceptable, en relación al porcentaje de animales anémicos y al incremento del peso corporal
Introduction: the scientific and technological development of biological and biomedical sciences has been possible due to the use of experimental animal models. Iron- (Fe-) deficiency anemia affects about one third of the world population. Just weaned rats have been the animal model most commonly used to obtain an experimental biomodel of anemia. The disease is obtained by the hemoglobin (Hb) depletion method, feeding the animal an iron-deficient diet. Objective: evaluate the efficacy of a purified diet based on casein to obtain anemic rats. Method: a study was conducted of 40 just weaned (21-24 days) Sprague Dawley rats, 20 of each sex. The animals were housed in groups of 3 rats of the same sex in stainless steel boxes with mesh bottoms. For 8 weeks the animals were administered deionized water and a casein diet of 12.58 percent protein and 1.28 mgFe/kg. Body weight was measured every two weeks. Hb concentration was gauged from the fourth week onwards. Results: a significant increase in body weight was obtained, with no differences between male and female rats. The criterion for anemia was at least a 30 percent decrease in Hb with respect to the average baseline value per group. The percentage of anemic animals at 8 weeks was higher for females (75 percent ) than for males (60 percent ) Conclusions: the diet used for the study made it possible to obtain female anemic rats with acceptable efficiency in relation to the percentage of anemic animals and the increase in body weight