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ST Depression, Arrhythmia, Vagal Dominance, and Reduced Cardiac Micro-RNA in Particulate-Exposed Rats
- Source :
- American Journal of Respiratory Cell and Molecular Biology. 44:185-196
- Publication Year :
- 2011
- Publisher :
- American Thoracic Society, 2011.
-
Abstract
- Recently, investigators demonstrated associations between fine particulate matter (PM)-associated metals and adverse health effects. Residual oil fly ash (ROFA), a waste product of fossil fuel combustion from boilers, is rich in the transition metals Fe, Ni, and V, and when released as a fugitive particle, is an important contributor to ambient fine particulate air pollution. We hypothesized that a single-inhalation exposure to transition metal-rich PM will cause concentration-dependent cardiovascular toxicity in spontaneously hypertensive (SH) rats. Rats implanted with telemeters to monitor heart rate and electrocardiogram were exposed once by nose-only inhalation for 4 hours to 3.5 mg/m(3), 1.0 mg/m(3), or 0.45 mg/m(3) of a synthetic PM (dried salt solution), similar in composition to a well-studied ROFA sample consisting of Fe, Ni, and V. Exposure to the highest concentration of PM decreased T-wave amplitude and area, caused ST depression, reduced heart rate (HR), and increased nonconducted P-wave arrhythmias. These changes were accompanied by increased pulmonary inflammation, lung resistance, and vagal tone, as indicated by changes in markers of HR variability (increased root of the mean of squared differences of adjacent RR intervals [RMSSD], low frequency [LF], high frequency [HF], and decreased LF/HF), and attenuated myocardial micro-RNA (RNA segments that suppress translation by targeting messenger RNA) expression. The low and intermediate concentrations of PM had less effect on the inflammatory, HR variability, and micro-RNA endpoints, but still caused significant reductions in HR. In addition, the intermediate concentration caused ST depression and increased QRS area, whereas the low concentration increased the T-wave parameters. Thus, PM-induced cardiac dysfunction is mediated by multiple mechanisms that may be dependent on PM concentration and myocardial vulnerability (this abstract does not reflect the policy of the United States Environmental Protection Agency).
- Subjects :
- Male
Pulmonary and Respiratory Medicine
Fine particulate
Pulmonary toxicity
Heart Ventricles
Clinical Biochemistry
Cardiovascular System
Coal Ash
Toxicology
Electrocardiography
Animal science
Heart Rate
Rats, Inbred SHR
Heart rate
Transition Elements
medicine
Animals
Telemetry
Potassium Channels, Inwardly Rectifying
Molecular Biology
ST depression
Inhalation
Chemistry
Airway Resistance
Arrhythmias, Cardiac
Vagus Nerve
Cell Biology
Particulates
Carbon
Rats
MicroRNAs
Connexin 43
Fly ash
Particulate Matter
Composition (visual arts)
Inflammation Mediators
medicine.symptom
Bronchoalveolar Lavage Fluid
Subjects
Details
- ISSN :
- 15354989 and 10441549
- Volume :
- 44
- Database :
- OpenAIRE
- Journal :
- American Journal of Respiratory Cell and Molecular Biology
- Accession number :
- edsair.doi.dedup.....347d182b4af22dcef76e5bfc078a713c