Body weight gain in rats by a high-fat diet produces chronodisruption in activity/inactivity circadian rhythm

Abstract

In the last few decades, obesity has become one of the most important public health problems. Adipose tissue is an active endocrine tissue which follows a rhythmic pattern in its functions and may produce alterations in certain circadian rhythms. Our aim was to evaluate whether the locomotor activity circadian rhythm could be modified by a hypercaloric diet in rodents. Two groups were considered in the experiment: 16 rats were used as a control group and were fed standard chow; the other group comprised 16 rats fed a high-fat diet (35.8% fat, 35% glucides). The trial lasted 16 weeks. Body weight was measured every week, and a blood sample was extracted every two weeks to quantify triglyceride levels. The activity/inactivity circadian rhythm was logged through actimetry throughout the trial, and analysed using the DAS 24© software package. At the end of the experiment, the high-fat fed rats had obese-like body weights and high plasma triglyceride levels, and, compared with the control group, increased diurnal activity, decreased nocturnal activity, reductions in amplitude, midline estimating statistic of rhythm, acrophase and interdaily stability, and increases in intradaily variability of their activity rhythms. The results thus show how obesity can lead to symptoms of chronodisruption in the body similar to those of ageing.

Activity/inactivity circadian rhythm shows high similarities between young obesity-induced rats and old rats

“…These populations suffer from lower amplitude, advanced phase, longer sleep onset and greater locomotor activity, and lower sleep efficiency with respect to young individuals (7,30,39). These circadian rhythm impairments have been found in other pathologies such as Alzheimer's disease, depression, schizophrenia, vascular disorders, metabolic syndrome, and obesity, among others (7,19,23,47).…”

High-fat diet and glucose and albumin circadian rhythms’ chronodisruption in rats

“…Previous studies associated this kind of alterations with obesity and sleep/wake circadian rhythm disorders (Bravo et al, 2014;Kalsbeek et al, 2014). Glucose circadian data showed clear symptoms of chronodisruption as can be observed in MESOR, amplitude, and acrophase, which showed different trends regarding the control group, the acrophase of glucose being the most evident parameter.…”

“…For this reason, in the present research, we used a high-fat diet designed to induce animals to obesity with every requirement (Hariri and Thibault, 2010). Previous works about obesity-induced diets established study periods longer than ours (11 weeks), which varied between 15 and 16 weeks (Laposky et al, 2006;Ríos Lugo et al, 2010;Nagatomo et al, 2012;Bravo et al, 2014). Moreover, in this assay, a diet with a lipid percentage of 60% and a carbohydrate percentage of 18.5% was used, while the previously mentioned articles had a lipid composition of 34.9%-35.8% and a carbohydrate composition of 25.9%-35%.…”

“…Both overweight and obesity show many characteristics such as high body mass index, endothelial dysfunction, atherosclerosis, hypertension, insulin resistance, and consequently diabetes mellitus type II, among other physiological disorders (Aranceta et al, 2006;Bravo et al, 2014). Several studies focused on laboratory animals have used cafeteria diets.…”

“…Obesity and overweight are problems that are continually growing from a public health point of view and they are considered as main causes of pathologic disorders such as metabolic syndrome or cardiovascular diseases (Bravo et al, 2014). Moreover, the most recent data from the World Health Organization show that this epidemic not only affects developed countries, but are also spreading in emerging countries (http://www.who.int/ dietphysicalactivity/childhood/en/; Peralta et al, 2015).…”