CARDIOREGULATORY EFFECTS OF PARTICULATE MATTERS ON SPONTANEOUSLY HYPERTENSIVE RATS
Date Issued
2006
Date
2006
Author(s)
Chang, Chuen-Chau
DOI
zh-TW
Abstract
Air pollution has been associated with cardiovascular diseases in epidemiology, but the underlying mechanisms remained to be explored. We applied heart rate variability (HRV) on spontaneously hypertensive rats (SHR) receiving particulate matters (PM) or their major components to demonstrate the biological plausibility.
In the first part of the thesis, concentrated ambient particles (CAPs) were inhaled by radiotelemtered SHR via nose only exposure system. Statistical analysis revealed increased heart rate, mean blood pressure, and myocardial contractility during the exposure hours. Concurrent decreases in the 5-minute standard deviation of the normal-to-normal intervals (SDNN) and the 5-minute root mean square of successive differences of adjacent normal-to-normal intervals (RMSSD) were also demonstrated. These findings were also observed in exposures to CAPs collected during an episode of Asian dust storm.
In the latter part of the thesis, ultrafine carbon black (ufCB, 14 nm), fine carbon black (fCB, 280 nm), Fe2(SO4)3 and NiSO4 were all exposed to SHR via intratractheal instillation at two doses. The results showed little changes of heart rate and HRV indices during fCB exposures. Dynamic changes were observed in exposures to ufCB, Fe and Ni. Obvious interactions were also demonstrated during combined exposures to ufCB and Fe or Ni.
We conclude that CAPs inhalation may increase heart rate, blood pressure, and myocardial contractility in spontaneously hypertensive rats. The study also shows that QAI, which reflexes the myocardial contractility, may be a sensitive and useful indicator in the study of PM-related cardiovascular toxicity. This set of outcome measurements is capable of demonstrating the cardiovascular toxicities of CAPs collected during an episode of Asian dust storm.
Aside from the alterations in heart rate, blood pressure, and myocardial contractility, CAPs inhalation may also alter cardiac autonomic function, resulting in changes in heart rate variability (HRV) parameters including SDNN and RMSSD. HRV measurements, on the other hand, are sensitive enough to demonstrate the phasic changes and the interactions of toxic responses induced by ufCB and transition metals instillation. Conversely, interactions among multiple copollutants might be important in the synthesis of air pollution health effects, and that mathematical summation of componential toxic responses might not be enough in the estimation of real life exposure.
Subjects
空氣污染
空氣懸浮微粒
心血管疾病
心跳速率變異性分析
生理訊號遙測術
Air pollution
Particulte matter
Cardiovascular disease
Hear rate vairability
Radiotelemetry
Spontaneously hypertensive rats
Type
thesis
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