title: The cessation of the long-term exposure to low doses of mercury ameliorates the increase in systolic blood pressure and vascular damage in rats.
abstract: This study aimed to verify whether a prolonged exposure to low-level mercury promotes haemodynamic disorders and studied the reversibility of this vascular damage. Rats were divided into seven groups: three control groups received saline solution (im) for 30, 60 or 90 days; two groups received HgCl2(im, first dose, 4.6μg/kg, subsequent doses 0.07μg/kg/day) for 30 or 60 days; two groups received HgCl2for 30 or 60 days (im, same doses) followed by a 30-day washout period. Systolic blood pressure (SBP) was measured, along with analysis of vascular response to acetylcholine (ACh) and phenylephrine (Phe) in the absence and presence of endothelium, a nitric oxide (NO) synthase inhibitor, an NADPH oxidase inhibitor, superoxide dismutase, a non-selective cyclooxygenase (COX) inhibitor and an AT1 receptor blocker. Reactive oxygen species (ROS) levels and antioxidant power were measured in plasma. HgCl2exposure for 30 and 60 days: a) reduced the endothelium-dependent relaxation; b) increased the Phe-induced contraction and the contribution of ROS, COX-derived vasoconstrictor prostanoids and angiotensin II acting on AT1 receptors to this response while the NO participation was reduced; c) increased the oxidative stress in plasma; d) increased the SBP only after 60 days of exposure. After the cessation of HgCl2exposure, SBP, endothelium-dependent relaxation, Phe-induced contraction and the oxidative stress were normalised, despite the persistence of the increased COX-derived prostanoids. These results demonstrated that long-term HgCl2exposure increases SBP as a consequence of vascular dysfunction; however, after HgCl2removal from the environment the vascular function ameliorates.
authors.affiliation: Postgraduate Program in Biochemistry, Universidade Federal do Pampa, Uruguaiana, RS, Brazil.
authors.forename: Danize Aparecida
authors.initials: DA
authors.lastname: Rizzetti
authors.affiliation: Postgraduate Program in Biochemistry, Universidade Federal do Pampa, Uruguaiana, RS, Brazil.
authors.forename: João Guilherme Dini
authors.initials: JG
authors.lastname: Torres
authors.affiliation: Postgraduate Program in Biochemistry, Universidade Federal do Pampa, Uruguaiana, RS, Brazil.
authors.forename: Alyne Goulart
authors.initials: AG
authors.lastname: Escobar
authors.affiliation: Postgraduate Program in Biochemistry, Universidade Federal do Pampa, Uruguaiana, RS, Brazil; Department of Basic Health Sciences, Universidad Rey Juan Carlos, Alcorcón, Spain; Bioactivity and Food Analysis Laboratory, Instituto de Investigación en Ciencias de la Alimentación, Madrid, Spain; Department of Physiological Sciences, Universidade Federal do Espírito Santo, Vitória, ES, Brazil; Department of Pharmacology, Universidad Autónoma de Madrid, Madrid, Spain.
authors.forename: Taiz Martins
authors.initials: TM
authors.lastname: da Silva
authors.affiliation: Postgraduate Program in Biochemistry, Universidade Federal do Pampa, Uruguaiana, RS, Brazil.
authors.forename: Paola Zambelli
authors.initials: PZ
authors.lastname: Moraes
authors.affiliation: Department of Basic Health Sciences, Universidad Rey Juan Carlos, Alcorcón, Spain.
authors.forename: Raquel
authors.initials: R
authors.lastname: Hernanz
authors.affiliation: Postgraduate Program in Biochemistry, Universidade Federal do Pampa, Uruguaiana, RS, Brazil.
authors.forename: Franck Maciel
authors.initials: FM
authors.lastname: Peçanha
authors.affiliation: Bioactivity and Food Analysis Laboratory, Instituto de Investigación en Ciencias de la Alimentación, Madrid, Spain.
authors.forename: Marta Miguel
authors.initials: MM
authors.lastname: Castro
authors.affiliation: Department of Physiological Sciences, Universidade Federal do Espírito Santo, Vitória, ES, Brazil.
authors.forename: Dalton Valentim
authors.initials: DV
authors.lastname: Vassallo
authors.affiliation: Department of Pharmacology, Universidad Autónoma de Madrid, Madrid, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Salaices
authors.affiliation: Department of Basic Health Sciences, Universidad Rey Juan Carlos, Alcorcón, Spain.
authors.forename: Maria Jesús
authors.initials: MJ
authors.lastname: Alonso
authors.affiliation: Postgraduate Program in Biochemistry, Universidade Federal do Pampa, Uruguaiana, RS, Brazil. Electronic address: giuliawp@gmail.com.
authors.forename: Giulia Alessandra
authors.initials: GA
authors.lastname: Wiggers
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology; D004785:Environmental Pollutants / Q000097:blood / Q000493:pharmacokinetics / Q000633:toxicity*; D066298:In Vitro Techniques; D008297:Male; D008628:Mercury / Q000097:blood / Q000493:pharmacokinetics / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects; D010656:Phenylephrine / Q000494:pharmacology; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D004785:Environmental Pollutants; D017382:Reactive Oxygen Species; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D010656:Phenylephrine; D008628:Mercury; D000109:Acetylcholine
keywords: Blood pressure; Cessation of exposure; Long-term exposure; Mercury; Oxidative stress