Abstract
BackgroundRisk factors associated with development of childhood disorders such as asthma and obesity include prematurity and intrauterine growth restriction. We recently demonstrated that exposure of Long Evans rats in early pregnancy to the air pollutant, ozone, resulted in reduced near‐term fetal growth. We propose to utilize this model of early life environmental stress to examine developmental origins of asthma later in life. Therefore, in this pilot study, we sought to improve the sensitivity of WBP to monitor lung volume growth in rats during development.MethodsSubset A male and female offspring from air‐ or 0.8 ppm ozone‐exposed dams (4h/day on gestational day 5 and 6) (n ≅ 6/group) were monitored weekly from postnatal day (PND) 13 to PND70 for changes in body weight and spontaneous ventilatory parameters [i.e., breathing frequency (f), tidal volume (TV), minute volume (MV), EF50 and Penh]. Data were first obtained using mouse and later rat WBP chambers with EMKA iox 2 software (SCIREQ, Montreal, Canada). To enhance tidal breathing, Subset B male offspring (n = 7; ≥ PND50) were used to optimize a CO2 challenge protocol (5–7.5% CO2) for up to 10 minutes under control conditions, and then later (PND81) to assess whether the CO2 challenge would also be tolerated acutely following exposure to ozone (0.4 or 0.8 ppm ×4h).ResultsSubset A offspring underwent rapid growth during the 8‐week study period with nearly 15‐fold increases in body weight in males and 10‐fold increases in females. Corresponding increases in TV (~0.2 to > 2.0 mL) were observed. In Subset B males, a 6% CO2 challenge for 6 minutes appeared optimal. Likewise, in Subset A rats at PND67, this CO2 challenge resulted in more uniform breathing, less movement‐related artifacts, and increased ventilatory effort (TV increased ~50%); although females were somewhat less responsive. Lastly, use of the 6% CO2 challenge immediately following ozone exposure of Subset B males more readily distinguished the resultant breathing pattern alterations and lung volume deficits occurring.ConclusionsAlthough the CO2‐enhanced lung volume measurements obtained herein are not equivalent to maximal, expiratory maneuvers (i.e., FEV1) as can be achieved in humans, this protocol was well tolerated and may provide a more sensitive, yet non‐invasive method of documenting differential lung growth trajectories in offspring— with or without prior in utero ozone exposure — as they undergo additional exposures during weanling and peri‐adolescent life stages. (Abstract does not reflect USEPA policy).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.