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.
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.
Authors: Michelle L Bell; Keita Ebisu; Roger D Peng; Jonathan M Samet; Francesca Dominici Journal: Am J Respir Crit Care Med Date: 2009-03-19 Impact factor: 21.405
Authors: Roger D Peng; Howard H Chang; Michelle L Bell; Aidan McDermott; Scott L Zeger; Jonathan M Samet; Francesca Dominici Journal: JAMA Date: 2008-05-14 Impact factor: 56.272
Authors: Naina Gour; Kuladeep Sudini; Syed Muaz Khalil; Ana M Rule; Peter Lees; Edward Gabrielson; John D Groopman; Stephane Lajoie; Anju Singh Journal: Environ Res Date: 2017-11-24 Impact factor: 6.498
Authors: Reuben Howden; Eva Gougian; Marcus Lawrence; Samantha Cividanes; Wesley Gladwell; Laura Miller-DeGraff; Page H Myers; D Clay Rouse; Robert B Devlin; Hye-Youn Cho; Steven R Kleeberger Journal: Oxid Med Cell Longev Date: 2013-04-22 Impact factor: 6.543