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Chronic Lead Exposure Increases Blood Pressure and Myocardial Contractility in Rats

We investigated the cardiovascular effects of lead exposure, emphasising its direct action on myocardial contractility. Male Wistar rats were sorted randomly into two groups: control (Ct) and treatment with 100 ppm of lead (Pb) in the drinking water. Blood pressure (BP) was measured weekly. At the e...

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Autores principales: Fioresi, Mirian, Simões, Maylla Ronacher, Furieri, Lorena Barros, Broseghini-Filho, Gilson Brás, Vescovi, Marcos Vinícius A., Stefanon, Ivanita, Vassallo, Dalton Valentim
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4026242/
https://www.ncbi.nlm.nih.gov/pubmed/24841481
http://dx.doi.org/10.1371/journal.pone.0096900
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author Fioresi, Mirian
Simões, Maylla Ronacher
Furieri, Lorena Barros
Broseghini-Filho, Gilson Brás
Vescovi, Marcos Vinícius A.
Stefanon, Ivanita
Vassallo, Dalton Valentim
author_facet Fioresi, Mirian
Simões, Maylla Ronacher
Furieri, Lorena Barros
Broseghini-Filho, Gilson Brás
Vescovi, Marcos Vinícius A.
Stefanon, Ivanita
Vassallo, Dalton Valentim
author_sort Fioresi, Mirian
collection PubMed
description We investigated the cardiovascular effects of lead exposure, emphasising its direct action on myocardial contractility. Male Wistar rats were sorted randomly into two groups: control (Ct) and treatment with 100 ppm of lead (Pb) in the drinking water. Blood pressure (BP) was measured weekly. At the end of the treatment period, the animals were anaesthetised and haemodynamic parameters and contractility of the left ventricular papillary muscles were recorded. Blood and tissue samples were properly stored for further biochemical investigations. Statistical analyses were considered to be significant at p<0.05. The lead concentrations in the blood reached approximately 13 µg/dL, while the bone was the site of the highest deposition of this metal. BP in the Pb-treated group was higher from the first week of lead exposure and remained at the same level over the next four weeks. Haemodynamic evaluations revealed increases in systolic (Ct: 96±3.79 vs. Pb: 116±1.37 mmHg) and diastolic blood pressure (Ct: 60±2.93 vs. Pb: 70±3.38 mmHg), left ventricular systolic pressure (Ct: 104±5.85 vs. Pb: 120±2.51 mmHg) and heart rate (Ct: 307±10 vs. Pb: 348±16 bpm). Lead treatment did not alter the force and time derivatives of the force of left ventricular papillary muscles that were contracting isometrically. However, our results are suggestive of changes in the kinetics of calcium (Ca(++)) in cardiomyocytes increased transarcolemmal Ca(++) influx, low Ca(++) uptake by the sarcoplasmic reticulum and high extrusion by the sarcolemma. Altogether, these results show that despite the increased Ca(++) influx that was induced by lead exposure, the myocytes had regulatory mechanisms that prevented increases in force, as evidenced in vivo by the increased systolic ventricular pressure.
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spelling pubmed-40262422014-05-21 Chronic Lead Exposure Increases Blood Pressure and Myocardial Contractility in Rats Fioresi, Mirian Simões, Maylla Ronacher Furieri, Lorena Barros Broseghini-Filho, Gilson Brás Vescovi, Marcos Vinícius A. Stefanon, Ivanita Vassallo, Dalton Valentim PLoS One Research Article We investigated the cardiovascular effects of lead exposure, emphasising its direct action on myocardial contractility. Male Wistar rats were sorted randomly into two groups: control (Ct) and treatment with 100 ppm of lead (Pb) in the drinking water. Blood pressure (BP) was measured weekly. At the end of the treatment period, the animals were anaesthetised and haemodynamic parameters and contractility of the left ventricular papillary muscles were recorded. Blood and tissue samples were properly stored for further biochemical investigations. Statistical analyses were considered to be significant at p<0.05. The lead concentrations in the blood reached approximately 13 µg/dL, while the bone was the site of the highest deposition of this metal. BP in the Pb-treated group was higher from the first week of lead exposure and remained at the same level over the next four weeks. Haemodynamic evaluations revealed increases in systolic (Ct: 96±3.79 vs. Pb: 116±1.37 mmHg) and diastolic blood pressure (Ct: 60±2.93 vs. Pb: 70±3.38 mmHg), left ventricular systolic pressure (Ct: 104±5.85 vs. Pb: 120±2.51 mmHg) and heart rate (Ct: 307±10 vs. Pb: 348±16 bpm). Lead treatment did not alter the force and time derivatives of the force of left ventricular papillary muscles that were contracting isometrically. However, our results are suggestive of changes in the kinetics of calcium (Ca(++)) in cardiomyocytes increased transarcolemmal Ca(++) influx, low Ca(++) uptake by the sarcoplasmic reticulum and high extrusion by the sarcolemma. Altogether, these results show that despite the increased Ca(++) influx that was induced by lead exposure, the myocytes had regulatory mechanisms that prevented increases in force, as evidenced in vivo by the increased systolic ventricular pressure. Public Library of Science 2014-05-19 /pmc/articles/PMC4026242/ /pubmed/24841481 http://dx.doi.org/10.1371/journal.pone.0096900 Text en © 2014 Fioresi et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Fioresi, Mirian
Simões, Maylla Ronacher
Furieri, Lorena Barros
Broseghini-Filho, Gilson Brás
Vescovi, Marcos Vinícius A.
Stefanon, Ivanita
Vassallo, Dalton Valentim
Chronic Lead Exposure Increases Blood Pressure and Myocardial Contractility in Rats
title Chronic Lead Exposure Increases Blood Pressure and Myocardial Contractility in Rats
title_full Chronic Lead Exposure Increases Blood Pressure and Myocardial Contractility in Rats
title_fullStr Chronic Lead Exposure Increases Blood Pressure and Myocardial Contractility in Rats
title_full_unstemmed Chronic Lead Exposure Increases Blood Pressure and Myocardial Contractility in Rats
title_short Chronic Lead Exposure Increases Blood Pressure and Myocardial Contractility in Rats
title_sort chronic lead exposure increases blood pressure and myocardial contractility in rats
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4026242/
https://www.ncbi.nlm.nih.gov/pubmed/24841481
http://dx.doi.org/10.1371/journal.pone.0096900
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