TY - JOUR T1 - Micron-sized particle deposition in the developing rodent lung JF - European Respiratory Journal JO - Eur Respir J VL - 38 IS - Suppl 55 SP - 3216 AU - Holger Schulz AU - Gunter Eder AU - Ines Bolle AU - Akira Tsuda AU - Stefan Karrasch Y1 - 2011/09/01 UR - http://erj.ersjournals.com/content/38/Suppl_55/3216.abstract N2 - Background: Little is known about the effects of postnatal developmental changes in lung architecture and breathing patterns on intrapulmonary particle deposition. We measured deposition on postnatal days (P) 7, 14, 21, 35 and 90 in WKY rats, whose lung development largely parallels that of humans.Methods: Intrapulmonary deposition of 2 μm sebacate particles was determined in anaesthetized, intubated, spontaneously breathing rats. Continuous measurement of aerosol concentration as a function of respired volume was accomplished by aerosol photometry (Karrasch et al. 2009). Respiratory parameters were determined by whole-body plethysmography.Results: Tidal volume increased more than 10-fold from P7 (0.19 mL) to P90 (2.1 mL) while respiratory rate declined from 182 to 113/min. Deposition per breath was lowest (9%) at P7 and P90 and markedly higher at P35 (almost 16%). Structural changes of the alveolar region include an increase in surface area from 744 cm2 at P7 to 6536 cm2 at P90 (Bolle et al. 2008). Consequently, particle deposition per unit time and surface area (DST) peaked at P35 and showed a minimum at P90 indicating that DST is always higher in the developing than in the adult lung. At an inhaled particle number concentration of 10E5/cm3 an estimated 450, 690 and 290 particles are deposited per min*cm2 at P7, P35 and P90, respectively.Discussion: Micron-sized particle deposition was dependent on the stage of postnatal lung development in rats. A maximum was observed during late alveolarisation (P35), which corresponds to human lungs of about 8 years of age. Children at this age may therefore be more susceptible to airborne environmental health hazards.Supported by NIH-Grant HL070542 ER -