title: Melatonin normalizes clinical and biochemical parameters of mild inflammation in diet-induced metabolic syndrome in rats.
abstract: The objective of this study was to evaluate the efficacy of melatonin to affect mild inflammation in the metabolic syndrome (MS) induced by a high-fat diet in rats. Adult Wistar male rats were divided into four groups (n = 16/group): (i) control diet (3% fat); (ii) high-fat (35%) diet; (iii) high-fat diet + melatonin; and (iv) melatonin. Rats had free access to high-fat or control chow and one of the following drinking solutions for 10 wk: (a) tap water; (b) 25 μg/mL of melatonin. Plasma interleukin (IL)-1β, IL-4, IL-6, IL-10, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, and C-reactive protein (CRP) were measured at two time intervals, that is, the middle of daylight period and the middle of the scotophase. In addition, a number of somatic and metabolic components employed clinically to monitor the MS were measured. Melatonin decreased the augmented circulating levels of IL-1β, IL-6, TNF-α, IFN-γ, and CRP seen in obese rats and restored the depressed levels of IL-4 and IL-10. Rats fed with the high-fat diet showed significantly higher body weights and augmented systolic blood pressure from the third and fourth week onwards, respectively, melatonin effectively preventing these changes. In high-fat-fed rats, circulating low-density lipoprotein-cholesterol, total cholesterol, and triglyceride concentration augmented significantly, melatonin being effective to counteract these changes. Melatonin-treated rats showed a decreased insulin resistance, the highest values of plasma high-density lipoprotein-cholesterol, and the lowest values of plasma uric acid. The results indicate that melatonin is able to normalize the altered biochemical pro-inflammatory profile seen in rats fed with a high-fat diet.
authors.affiliation: Department of Biochemistry and Molecular Biology III, Faculty of Medicine, Universidad Complutense, Madrid, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Cano Barquilla
authors.forename: Eleonora S
authors.initials: ES
authors.lastname: Pagano
authors.forename: Vanesa
authors.initials: V
authors.lastname: Jiménez-Ortega
authors.forename: Pilar
authors.initials: P
authors.lastname: Fernández-Mateos
authors.forename: Ana I
authors.initials: AI
authors.lastname: Esquifino
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Cardinali
mesh_terms: D000818:Animals; D007249:Inflammation / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D024821:Metabolic Syndrome / Q000378:metabolism / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D008550:Melatonin
keywords: cytokines; dyslipidemia; glucose tolerance; high-fat diet; hypertension; inflammation; uric acid