Effects of intratracheal budesonide during early postnatal life on lung maturity of premature fetal rabbits

Abstract

Aim: This study aimed to study the effects of intratracheal instillation of budesonide on lung maturity of premature fetal rabbits. The developmental pattern of pulmonary alveoli in rabbits is similar to that in humans.Method: Fetal rabbits were taken out from female rabbits on the 28th day of pregnancy (full term = 31 days) by cesarean section (c-section). The fetal rabbits were divided into four groups: control (normal saline, NS), budesonide (budesonide, BUD), calf pulmonary surfactant for injection (pulmonary surfactant, PS), and calf pulmonary surfactant + budesonide for injection (pulmonary surfactant + budesonide, PS + BUD).All premature rabbits were kept warm after c-section. After 15-min autonomous respiration, a tracheal cannula was implemented for instilling NS, BUD, PS, and PS + BUD. The morphology of lung tissues of premature fetal rabbits was analyzed using optical and electron microscopes. Surfactant protein B (SP-B) mRNA and protein levels in lung tissues were determined using polymerase chain reaction and Western blotting, respectively.Result: Intratracheal instillation of BUD could increase the alveolar area of the fetal rabbits (P < 0.01), decrease the alveolar wall thickness (P < 0.01), and increase the mean density of lamellar bodies (P < 0.05) and SP-B protein levels in type II epithelial cells of pulmonary alveoli (P < 0.05).Conclusion: Intratracheal instillation of BUD during early postnatal life is effective in promoting alveolarization and increasing SP-B expression, the pro-pulmonary maturity of BUD combined with PS is superior to that of BUD or PS alone. However, the longterm effect of BUD on lung development needs further exploration. K E Y W O R D Sbudesonide, lung maturity, premature rabbit, pulmonary surfactant, pulmonary surfactant protein B

2018 year in review: Part 2 of 4: Neonatal lung disease

“…Li and colleagues administered intratracheal budesonide to fetal rabbits at 28 days gestation (31 days = term) one hour before harvesting lungs and showed augmented SP‐B mRNA expression and improved lung morphology. These results are indeed remarkable given what has typically been described for the time to onset of action and underscores more recent evidence showing that steroid effects may begin within minutes of administration .…”

Models of Intrauterine growth restriction and fetal programming in rabbits

“…However, at this age, the fetal lungs are structurally immature (Snyder, Mendelson, & Johnston, ). Indeed, the first terminal bronchiole appears between GD23–24 (Karnak, Müftüoğlu, Cakar, & Tanyel, ) and alveolar wall thickness decrease by 40% just before birth (Li et al, ). At birth, rabbit kits possess 5% of their total number of alveoli, which rapidly increase in density during the immediate postnatal period (Li et al, ).…”

“…Indeed, the first terminal bronchiole appears between GD23–24 (Karnak, Müftüoğlu, Cakar, & Tanyel, ) and alveolar wall thickness decrease by 40% just before birth (Li et al, ). At birth, rabbit kits possess 5% of their total number of alveoli, which rapidly increase in density during the immediate postnatal period (Li et al, ). Lung volume also increases by 20‐fold between birth and adulthood in rabbits (Li et al, ).…”

“…At birth, rabbit kits possess 5% of their total number of alveoli, which rapidly increase in density during the immediate postnatal period (Li et al, ). Lung volume also increases by 20‐fold between birth and adulthood in rabbits (Li et al, ). This pattern of perinatal and postnatal lung maturation in the rabbit is similar to the human (Li et al, ).…”

“…Lung volume also increases by 20‐fold between birth and adulthood in rabbits (Li et al, ). This pattern of perinatal and postnatal lung maturation in the rabbit is similar to the human (Li et al, ).…”