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Micron-sized intrapulmonary particle deposition in the developing rat lung.
Holger Schulz1, Gunter Eder, Ines Bolle
1Institute of Epidemiology I, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstädter Landstr. 1, D-85764 Neuherberg/Munich, Germany. schulz@helmholtz-muenchen.de
Journal of Applied Physiology (Bethesda, Md. : 1985)
|December 14, 2011
Summary
Particle deposition in developing lungs changes with age. Micron-sized particles are most readily deposited in rat lungs at postnatal day 35, a stage comparable to eight-year-old children, suggesting increased susceptibility to airborne hazards.
Area of Science:
- Pulmonary physiology
- Developmental biology
- Environmental health
Background:
- Postnatal lung development involves significant changes in architecture and breathing patterns.
- The impact of these developmental changes on intrapulmonary particle deposition is not well understood.
Purpose of the Study:
- To investigate how postnatal developmental changes in lung structure and breathing mechanics influence the deposition of inhaled particles.
- To assess the susceptibility of developing lungs to environmental airborne hazards.
Main Methods:
- Particle deposition of 2-μm sebacate particles was measured in Wistar-Kyoto rats from postnatal day 7 (P7) to P90 using aerosol photometry.
- Respiratory parameters including tidal volume and respiratory rate were determined using body plethysmography.
- Structural lung changes, specifically alveolar surface area, were analyzed.
Main Results:
- Breath-specific particle deposition was lowest at P7 and P90, but markedly higher at P35 (nearly 16%).
- Particle deposition per unit time and surface area peaked at P35, with an estimated 690 particles/(min × cm²) at an inhaled concentration of 10⁵/cm³.
- Multiple regression analysis indicated that deposition is significantly influenced by lung structural components (mean linear intercept) and breathing parameters (tidal volume, respiratory rate).
Conclusions:
- Micron-sized particle deposition in the lungs is highly dependent on the stage of postnatal development.
- A peak deposition was observed during late alveolarization (P35), a stage analogous to human lungs around eight years of age.
- Children at this developmental stage may exhibit increased vulnerability to inhaled environmental pollutants and airborne particles.
