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Silva V.C.,Sociedade Brasileira de Fisiologia SBFis | Silva V.C.,Federal University of Juiz de fora | Giusti-Paiva A.,Sociedade Brasileira de Fisiologia SBFis | Giusti-Paiva A.,Federal University of Alfenas
Brain, Behavior, and Immunity | Year: 2015

Sickness behavior is an expression of a motivational state triggered by activation of the peripheral innate immune system, whereby an organism reprioritizes its functions to fight infection. The relationship between thyroid hormone and immune cells is complex, and additional insights are needed about the involvement of the cross-talk between thyroid hormone, the central nervous system and immune function, as demonstrated by the consequences to sickness behavior. The aim of this work was to evaluate sickness behavior in hypothyroid mice. Control mice and mice treated with propylthiouracil (PTU) for 30. days (0.05%; added to drinking water) received a single dose of LPS (200. μg/kg; i.p.) or saline, and the behavioral response was assessed for 24. h. We provide evidence that thyroid status acts a modulator for the development of depressive-like and exploratory behaviors in mice that are subjected to an immunological challenge because the PTU pretreatment delayed the LPS-induced behavioral changes observed in an open field test and in a forced swimming test. This response was observed concomitantly with a lower thermal index until 4. h after the LPS administration. This result demonstrates that thyroid status modifies behavioral responses to immune challenge and suggests that thyroid hormones are essential for the manifestation of sickness behavior during endotoxemia. © 2014 Elsevier Inc.

Orlandi L.,Sociedade Brasileira de Fisiologia SBFis | Fonseca W.F.,Sociedade Brasileira de Fisiologia SBFis | Enes-Marques S.,Sociedade Brasileira de Fisiologia SBFis | Paffaro V.A.,Federal University of Alfenas | And 3 more authors.
Journal of Neuroimmunology | Year: 2015

This study investigated behavioral responses to an immune challenge among animals with fructose-induced metabolic disorders. Adult male Wistar rats were provided either water or a fructose solution (10%) for 5 weeks. Sickness behaviors were assessed 2 h following the injection of either a lipopolysaccharide (LPS) or vehicle. The rats were subjected to an open field test, a social interaction test, a food intake test and a fever evaluation. Cytokine expression was assessed in both adipose tissue and hypothalamus samples. The neural response was assessed in the forebrain immunohistochemistry for c-Fos. Compared with the control group, the fructose diet induced dyslipidemia and significantly higher plasma total cholesterol, HDL-cholesterol, triglyceride, and glucose levels as well as both epididymal and retroperitoneal adiposity. Furthermore, in response to LPS (1 mg/kg), the rats subjected to a fructose diet exhibited exacerbated sickness behaviors and accentuated febrile responses. LPS induced Fos protein expression in several areas of the brains of the control rats; however, higher numbers of Fos-positive cells were observed in the brains of the rats that were fed a fructose diet. Moreover, larger increases in cytokine expression were observed in both the hypothalamus and the adipose tissue of the obese rats compared with the control rats in response to LPS. In this study, fructose diets played an important role in both the induction of metabolic disorders and the modulation of sickness behaviors in response to an immunological challenge, most likely through the induction of cytokines in the hypothalamus. © 2015 Elsevier B.V..

de Matos M.A.,Sociedade Brasileira de Fisiologia SBFis | de Matos M.A.,Federal University of Vales do Jequitinhonha and Mucuri | Duarte T.C.,Federal University of Vales do Jequitinhonha and Mucuri | Ottone V.O.,Sociedade Brasileira de Fisiologia SBFis | And 16 more authors.
Cell Biochemistry and Function | Year: 2016

Obesity is a low-grade chronic inflammation condition, and macrophages, and possibly monocytes, are involved in the pathological outcomes of obesity. Physical exercise is a low-cost strategy to prevent and treat obesity, probably because of its anti-inflammatory action. We evaluated the percentage of CD16− and CD16+ monocyte subsets in obese insulin-resistant individuals and the effect of an exercise bout on the percentage of these cells. Twenty-seven volunteers were divided into three experimental groups: lean insulin sensitive, obese insulin sensitive and obese insulin resistant. Venous blood samples collected before and 1 h after an aerobic exercise session on a cycle ergometer were used for determination of monocyte subsets by flow cytometry. Insulin-resistant obese individuals have a higher percentage of CD16+ monocytes (14.8 ± 2.4%) than the lean group (10.0 ± 1.3%). A positive correlation of the percentage of CD16+ monocytes with body mass index and fasting plasma insulin levels was found. One bout of moderate exercise reduced the percentage of CD16+ monocytes by 10% in all the groups evaluated. Also, the absolute monocyte count, as well as all other leukocyte populations, in lean and obese individuals, increased after exercise. This fact may partially account for the observed reduction in the percentage of CD16+ cells in response to exercise. Insulin-resistant, but not insulin-sensitive obese individuals, have an increased percentage of CD16+ monocytes that can be slightly modulated by a single bout of moderate aerobic exercise. These findings may be clinically relevant to the population studied, considering the involvement of CD16+ monocytes in the pathophysiology of obesity. Copyright © 2016 John Wiley & Sons, Ltd. Significance of the Study: Obesity is now considered to be an inflammatory condition associated with many pathological consequences, including insulin resistance. It is proposed that insulin resistance contributes to the aggravation of the inflammatory dysfunction in obesity. The effect of obesity on the percentage of monocytes was previously observed in class II and III obese individuals who presented other alterations in addition to insulin resistance. In this study we observed that insulin-resistant obese individuals, but not insulin-sensitive ones, had an increased percentage of CD14+CD16+ monocytes. This fact shows that a dysfunction of the monocyte percentage in class I obese individuals is only seen when this condition is associated with insulin resistance. Copyright © 2016 John Wiley & Sons, Ltd.

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