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Updated: May 16, 2026
Evaluation of Respiratory System Mechanics in Mice using the Forced Oscillation Technique
Published on: May 15, 2013
The effects of age and carbon black on airway resistance in mice
Blake A Bennett1, Wayne Mitzner, Clarke G Tankersley
1Department of Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.
Context:
Ambient particulate matter (PM) is associated with acute exacerbations of airflow obstruction. Additionally, elderly individuals are more susceptible to increased functional morbidity following acute PM exposure.
Objective:
The purpose of this study is to determine the aging effects of PM exposure on the responsiveness of airway smooth muscle in mice. We hypothesized that airway reactivity induced by methacholine (Mch) will increase with age in PM exposed mice.
Materials And Methods:
Male C57BL/6 (B6) mice at 11, 39, 67, and 96 weeks of age were exposed to carbon black (CB) or room air (RA) for 3 h on 3 consecutive days. One day after the last exposure, mice were anesthetized and airways resistance (R(aw)) was measured by forced oscillation following half-log dose increases of aerosolized Mch.
Results:
Baseline R(aw) was significantly lower in 67 and 96 week mice compared to 11-week mice (p < 0.05). In RA exposed mice, an age-dependent decline in Mch-induced airway reactivity occurred in association with the highest Mch doses at ages 67 and 96 weeks (p < 0.05). A significantly (p < 0.05) greater Mch-induced R(aw) response occurred in 67-week mice exposed to CB compared with age-matched RA-exposed mice.
Discussion And Conclusion:
Our results show a progressive decrease in the Mch-induced R(aw) response with age in mice. The effect of CB exposure resulted in greater airway reactivity in middle-aged mice, which highlights the effects of PM exposure on the lung as it relates to increased morbidity and mortality with older age.
Insights
Aging increases susceptibility to particulate matter (PM) effects on airways. PM exposure worsened airway reactivity in middle-aged mice, indicating heightened risk with age.
Area of Science:
- Pulmonary medicine
- Environmental health
- Aging research
Background:
- Ambient particulate matter (PM) exposure is linked to acute exacerbations of airflow obstruction.
- Elderly individuals exhibit increased vulnerability to PM-induced functional morbidity.
Purpose of the Study:
- To investigate the impact of aging on airway smooth muscle responsiveness following PM exposure in mice.
- To determine if PM exposure exacerbates age-related changes in airway reactivity.
Main Methods:
- Mice (11, 39, 67, 96 weeks) were exposed to carbon black (CB) or room air (RA) for 3 days.
- Airway resistance (R(aw)) was measured via forced oscillation after methacholine (Mch) challenge.
Main Results:
- Baseline R(aw) decreased with age (67 and 96 weeks vs. 11 weeks).
- Mice exposed to RA showed an age-dependent decline in Mch-induced airway reactivity.
- CB exposure in 67-week-old mice significantly increased Mch-induced R(aw) compared to RA-exposed controls.
Conclusions:
- Airway responsiveness to Mch progressively decreases with age in mice.
- Carbon black exposure enhanced airway reactivity in middle-aged mice, underscoring PM's role in age-related respiratory morbidity.
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