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1.
Environ Res ; 155: 182-192, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28222365

RESUMO

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 HgCl2 for 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. HgCl2 exposure 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 HgCl2 exposure, 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 HgCl2 exposure increases SBP as a consequence of vascular dysfunction; however, after HgCl2 removal from the environment the vascular function ameliorates.


Assuntos
Poluentes Ambientais/toxicidade , Mercúrio/toxicidade , Acetilcolina/farmacologia , Animais , Aorta Torácica/efeitos dos fármacos , Aorta Torácica/fisiologia , Pressão Sanguínea/efeitos dos fármacos , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/fisiologia , Poluentes Ambientais/sangue , Poluentes Ambientais/farmacocinética , Técnicas In Vitro , Masculino , Mercúrio/sangue , Mercúrio/farmacocinética , Estresse Oxidativo/efeitos dos fármacos , Fenilefrina/farmacologia , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo , Vasoconstritores/farmacologia , Vasodilatadores/farmacologia
2.
Food Chem Toxicol ; 100: 253-264, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28043836

RESUMO

Oxidative stress in known to contribute to the male reproductive dysfunction induced by mercury (Hg). Our study tested the hypothesis that the egg white hydrolysate (EWH), a potent antioxidant in vitro, is able to prevent the effects of prolonged Hg exposure on male reproductive system in rats. For this, rats were treated for 60 days with: a) Untreated - saline solution (i.m.); b) Hydrolysate - EWH (1 g/kg/day, gavage); c) Mercury - HgCl2 (1st dose 4.6 µg/kg, subsequent doses 0.07 µg/kg/day, i.m.); d) Hydrolysate-Mercury. At the end of the treatment, sperm motility, count and morphological studies were performed; Reactive Oxygen Species (ROS) levels, lipid peroxidation, antioxidant capacity, histological and immunohistochemical assays on testis and epididymis were also carried out. As results, HgCl2-treatment decreased sperm number, increased sperm transit time in epididymis and impaired sperm morphology. However, these harmful effects were prevented by EWH. HgCl2-treatment also increased ROS levels, lipid peroxidation and antioxidant capacity in testis and epididymis as well as promoted testicular inflammation and histological changes in epididymis. EWH improved histological and immunohistochemical alterations, probably due to its antioxidant property. In conclusion, the EWH could represent a powerful natural alternative to protect the male reproductive system against Hg-induced sperm toxicity.


Assuntos
Antioxidantes/metabolismo , Clara de Ovo/química , Inflamação/tratamento farmacológico , Intoxicação por Mercúrio/tratamento farmacológico , Mercúrio/toxicidade , Fragmentos de Peptídeos/farmacologia , Reprodução/efeitos dos fármacos , Animais , Peso Corporal/efeitos dos fármacos , Epididimo/efeitos dos fármacos , Inflamação/induzido quimicamente , Inflamação/patologia , Masculino , Intoxicação por Mercúrio/etiologia , Intoxicação por Mercúrio/patologia , Estresse Oxidativo/efeitos dos fármacos , Fragmentos de Peptídeos/uso terapêutico , Ratos , Ratos Wistar , Contagem de Espermatozoides , Motilidade dos Espermatozoides/efeitos dos fármacos , Espermatozoides/efeitos dos fármacos , Espermatozoides/patologia , Testículo/efeitos dos fármacos , Testículo/patologia
3.
Brain Res ; 1646: 482-489, 2016 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-27350078

RESUMO

This study aims to investigate whether the egg white hydrolysate (EWH) acts on the neuropathic disorders associated with long-term Mercury (Hg) exposure in rats. 8- week-old male Wistar rats were treated for 60 days with: a) Control - saline solution (i.m.); b) Mercury - HgCl2 (1st dose 4.6µg/kg, subsequent doses 0.07µg/kg/day, i.m.); c) Hydrolysate - EWH (1g/kg/day, gavage); d) Mercury and Hydrolysate. Mechanical allodynia was assessed using Von Frey Hairs test; heat hyperalgesia by the plantar test; catalepsy by a modification of the "ring test" and spontaneous locomotor activity by a photocell activity chambers. Analyses were performed at 0, 30 and 60 days of treatment. Brain and plasma MDA, plasma NPSH and TNF-α determination and skin immunohistochemistry were performed at 60 days. Hg induced a reduction in mechanical sensitivity threshold at 30 and 60 days and in thermal sensitivity threshold at 60 days. At the end of treatment catalepsy was developed, but there was not significant alteration in spontaneous locomotor activity. Hg also increased brain and plasma MDA, plasma NPSH and TNF-α levels and the number of Merkel cell-neurite complex in the skin. EWH prevented the development of mechanical allodynia, thermal hyperalgesia and catalepsy induced by Hg and the increase in MDA concentration in brain and plasma and in the number of Merkel cell-neurite complex in the skin. In conclusion, EWH promotes neuroprotection against the toxic effects caused by Hg, demonstrating a beneficial therapeutic potential.


Assuntos
Mercúrio/toxicidade , Neuroproteção/efeitos dos fármacos , Fármacos Neuroprotetores/administração & dosagem , Doenças do Sistema Nervoso Periférico/induzido quimicamente , Doenças do Sistema Nervoso Periférico/complicações , Hidrolisados de Proteína/administração & dosagem , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Catalepsia/induzido quimicamente , Catalepsia/etiologia , Catalepsia/prevenção & controle , Clara de Ovo/química , Hiperalgesia/induzido quimicamente , Hiperalgesia/etiologia , Hiperalgesia/prevenção & controle , Peroxidação de Lipídeos/efeitos dos fármacos , Locomoção/efeitos dos fármacos , Masculino , Células de Merkel/metabolismo , Neuritos/metabolismo , Hidrolisados de Proteína/isolamento & purificação , Ratos , Ratos Wistar , Pele/metabolismo , Pele/patologia
4.
Neurochem Int ; 101: 30-37, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27732885

RESUMO

The study aimed to investigate whether the Egg White Hydrolysate (EWH) is able to prevent the recognition memory disorders associated with long-term Hg exposure in rats. For this, male Wistar rats were treated for 60 days with: a) Untreated: saline solution (i.m.); b) Hydrolysate: EWH (1 g/kg/day, gavage); c) Mercury: HgCl2 (1st dose 4.6 µg/kg, subsequent doses 0.07 µg/kg/day, i.m.); d) Hydrolysate-Mercury. Object recognition memory test was performed to verify Short (STM) and Long-Term Memory (LTM) and Open Field, Plus Maze and Tail Flick tests were performed as control for behavioural experiments. Reactive Oxygen Species (ROS) in the hippocampus were determined by the dichlorofluorescein diacetate (DCFH-DA) method, malondialdehyde (MDA) levels by TBARS, antioxidant power by FRAP assay and total Hg concentration by atomic fluorescence spectrometry. We confirm that the STM and LTM were impaired in adult rats exposed to Hg at low concentrations, which may be related to the increased metal deposition, ROS production and subsequent oxidative damage in the hippocampus. In addition, we demonstrated for the first time that EWH treatment is able to prevent memory impairment induced by Hg exposure, reducing Hg content and ROS production in the hippocampus. In conclusion, EWH prevents memory impairments induced by chronic exposure to low doses of Hg. These findings may represent a good public health strategy since they indicate that EWH is a promising candidate as a new natural therapy for heavy metal intoxication.


Assuntos
Antioxidantes/farmacologia , Peroxidação de Lipídeos/efeitos dos fármacos , Transtornos da Memória/tratamento farmacológico , Mercúrio/farmacologia , Hidrolisados de Proteína/metabolismo , Animais , Clara de Ovo , Masculino , Estresse Oxidativo/efeitos dos fármacos , Ratos Wistar , Espécies Reativas de Oxigênio/farmacologia
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