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Postnatal Growth Restriction Alters Lung Function and Structure In Juvenile Rats
Author(s) -
Ballard Craig R,
Zhou James,
Zuspan Katie,
Rebentisch Andrew,
Wang Haimei,
JossMoore Lisa
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.872.5
Subject(s) - lung , bronchopulmonary dysplasia , medicine , pulmonary compliance , context (archaeology) , litter , physiology , biology , gestational age , pregnancy , paleontology , agronomy , genetics
Background Preterm infants receiving respiratory support often experience extrauterine growth restriction (EUGR). EUGR in preterm infants occurs secondary to feeding intolerance and clinically indicated feeding volume restrictions. EUGR increases the severity and incidence of the chronic lung disease of infancy, bronchopulmonary dysplasia (BPD). BPD is characterized by impaired lung development, with decreased lung compliance, and increased lung resistance. Animal models demonstrate the importance of EUGR to lung development in the context of respiratory support. However, the isolated contribution of EUGR to lung development and function is unknown. We hypothesize that, in the juvenile rats, EUGR will impair alveolar development, decrease lung compliance, and increase lung resistance. Methods We induced EUGR in a rat model by cross fostering newborn rat pups to rat dams with litter sizes of 16 (EUGR) or 8 (control). Rat pup weight was measured every other day from birth to day of life 21 (d21). At postnatal d24, we measured alveolar wall thickness, second crest septal volume, and radial alveolar count (RAC) using ImageQuant software. At postnatal d24 we also measured lung compliance and resistance of the parenchyma (R Par ) and airway (R Air ) using a Flexivent System. Results Results are EUGR values as a percentage of control±SD (*=p<0.05). Rat pups in the EUGR group weighed significantly less (75±3%*) than control by postnatal d5 and continued to weigh less through d21 (70±5%*). Structural analysis of rat lungs revealed that EUGR rats had thicker alveolar walls than control in male (136±20%*) and female (134±32%*) rats, but no change in sepal density or RAC. EUGR decreased compliance in male (67±26%*) and female (66±25%*) rats. EUGR significantly increased R Par in both male (153±70%*) and female (157±56%*) rats and significantly increased R Air in male (111±25%*) and female (166±148%*) rats. Conclusion EUGR alters lung structure and function in juvenile rats. Given the role of elastin and elastic fiber formation in lung structure and function, we speculate that EUGR may disrupt elastin expression and fiber deposition. Ongoing studies are evaluating expression of elastin isoforms in the EUGR lung. Support or Funding Information Special thanks to the American Physiological Society for the Undergraduate Summer Research Fellowship that funded this research, and to Lisa Joss‐Moore and the University of Utah for hosting me in their lab. In addition, thanks you to James Zhou and Haimei Wang for help with collection of mechanics data, as well as Katie Zuspan and Andrew Rebentisch for conducting image analysis for structural data.