Developmental changes in diaphragm muscle function in the preterm and postnatal lamb
| Autor: | Peter B. Noble, Yong Song, Clare A Berry, W.A. Macdonald, J. Jane Pillow, C.J. McLean, Anthony J. Bakker, Gavin J. Pinniger, Tina Lavin |
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| Rok vydání: | 2012 |
| Předmět: |
Pulmonary and Respiratory Medicine
medicine.medical_specialty Diaphragm In Vitro Techniques Muscle Development Fetus Internal medicine Myosin medicine Respiratory muscle Animals RNA Messenger Respiratory system Sheep Respiratory distress Myosin Heavy Chains business.industry Gene Expression Profiling Skeletal muscle Respiratory Muscles Diaphragm (structural system) Endocrinology medicine.anatomical_structure Respiratory failure Animals Newborn Pediatrics Perinatology and Child Health Muscle Fatigue business Muscle Contraction |
| Zdroj: | Pediatric pulmonology. 48(7) |
| ISSN: | 1099-0496 |
| Popis: | Rationale The preterm diaphragm is structurally and functionally immature, potentially contributing to an increased risk of respiratory distress and failure. We investigated developmental changes in contractile function and susceptibility to fatigue of the costal diaphragm in the fetal lamb to understand factors contributing to the risk of developing diaphragm dysfunction and respiratory disorders. We hypothesized that the functional capacity of the diaphragm will vary with maturational stage as will its susceptibility to fatigue. Methods Lambs were studied at 75, 100, 125, 145, 154, 168, and 200 days postconceptional age (term = 147 days). Lambs were euthanized (sodium pentobarbitone, 100 mg/kg) either at delivery or immediately prior to post-mortem for postnatal lambs. Contractile function was assessed on longitudinal strips of intact muscle fibers and the remaining tissue frozen in liquid nitrogen for analysis of myosin heavy chain (MHC) mRNA expression and protein content. Results Fetal development of diaphragm function was characterized by a significant increase in maximum specific force, increased susceptibility to fatigue, reduced twitch contraction times, and a progressive increase in MHCI and MHCII protein content. Postnatally, there was a progressive decrease in the susceptibility to fatigue that coincided with an increase in the MHC I:II protein ratio. Conclusion These data indicate that the functional capacity of the diaphragm varies with maturational age and may be an important determinant of the susceptibility to preterm respiratory failure. Pediatr Pulmonol. 2013; 48:640–648. © 2013 Wiley Periodicals, Inc. |
| Databáze: | OpenAIRE |
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