Particle effects on heart-rate regulation in senescent mice

Clarke G. Tankersley, Matthew Campen, Alexis Bierman, Susan E. Flanders, Karl W. Broman, Richard Rabold

Research output: Contribution to journalArticle

Abstract

Because epidemiology studies consistently identify the elderly at risk for air pollution-related morbidity and mortality, we developed a model of senescent-dependent susceptibility based on indices of physiological aging. In the current study, we hypothesized that heart-rate regulation during particulate matter (PM) exposure differs with senescence-dependent susceptibility owing to variation in autonomic nervous control. Heart rate (HR) and heart-rate variability (HRV) parameters were measured from 162 samples of 2-min electrocardiograph (ECG) recordings in age-matched healthy (n = 5) and terminally senescent (n = 3) AKR mice during 3-h exposures to filtered-air (FA, day 1) and carbon black (CB, day 4; 3). On day 1, HR was significantly (p <.01) depressed during FA in terminally senescent mice. By day 4, HR was further slowed significantly (p <.01) due to the effects of CB exposure for 3 days. The combined effects of terminal senescence and CB exposure acted to depress HR to an average (±SEM) 445 ± 40 bpm, or ∼80 bpm lower compared to healthy HR responses. The change in rMSSD, an HRV parameter corresponding to relative influences of parasympathetic tone on HR, was significantly (p <.01) greater on day 1 and day 4 in terminally senescent mice compared to healthy mice. In contrast, the LF/HF ratio, an HRV parameter derived from spectral analysis indicating relative changes in cardiac sympathetic tone, was significantly (p <.01) depressed in terminally senescent mice on day 1. By day 4, significant increases in LF/HF were evident in healthy mice during CB exposure, suggesting that HR regulation was associated with an increase in sympathetic tone. Alternatively, terminally senescent mice appeared to modulate a lower HR without change in LF/HF ratio during CB exposure, suggesting an absence of sympathetic tone. In conclusion, older healthy mice increase cardiac sympathetic tone during PM exposure while terminally senescent mice show a greater PM-induced parasympathetic tone in regulating HR. The significance of the current results suggest that PM-induced HR regulatory changes may ultimately depend on the degree of physiological aging.

Original languageEnglish (US)
Pages (from-to)381-390
Number of pages10
JournalInhalation Toxicology
Volume16
Issue number6-7
DOIs
StatePublished - Jun 2004

Fingerprint

Heart Rate
Particulate Matter
Aging of materials
Inbred AKR Mouse
Soot
Epidemiology
Air Pollution
Air pollution
Spectrum analysis
Electrocardiography
Air
Morbidity
Scanning electron microscopy
Mortality

ASJC Scopus subject areas

  • Toxicology
  • Health, Toxicology and Mutagenesis

Cite this

Tankersley, C. G., Campen, M., Bierman, A., Flanders, S. E., Broman, K. W., & Rabold, R. (2004). Particle effects on heart-rate regulation in senescent mice. Inhalation Toxicology, 16(6-7), 381-390. https://doi.org/10.1080/08958370490439551

Particle effects on heart-rate regulation in senescent mice. / Tankersley, Clarke G.; Campen, Matthew; Bierman, Alexis; Flanders, Susan E.; Broman, Karl W.; Rabold, Richard.

In: Inhalation Toxicology, Vol. 16, No. 6-7, 06.2004, p. 381-390.

Research output: Contribution to journalArticle

Tankersley, CG, Campen, M, Bierman, A, Flanders, SE, Broman, KW & Rabold, R 2004, 'Particle effects on heart-rate regulation in senescent mice', Inhalation Toxicology, vol. 16, no. 6-7, pp. 381-390. https://doi.org/10.1080/08958370490439551
Tankersley CG, Campen M, Bierman A, Flanders SE, Broman KW, Rabold R. Particle effects on heart-rate regulation in senescent mice. Inhalation Toxicology. 2004 Jun;16(6-7):381-390. https://doi.org/10.1080/08958370490439551
Tankersley, Clarke G. ; Campen, Matthew ; Bierman, Alexis ; Flanders, Susan E. ; Broman, Karl W. ; Rabold, Richard. / Particle effects on heart-rate regulation in senescent mice. In: Inhalation Toxicology. 2004 ; Vol. 16, No. 6-7. pp. 381-390.
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