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Published on: October 19, 2013
Influence of Neonatal Exposure to Hyperoxia on Skeletal Muscle in a Rat Model
Kentaro Awata1, Irena Santosa2, Yoshiteru Arai1
1Department of Pediatrics and Adolescent Medicine, Graduate School of Medicine, Juntendo University, Bunkyo, Tokyo 113-8421, Japan.
Insights
Premature infants receiving oxygen support may experience impaired skeletal muscle development. Early-life hyperoxia exposure in rats led to muscle fiber atrophy, impacting growth into adulthood.
Area of Science:
- Biomedical Science
- Developmental Biology
- Physiology
Background:
- Premature infants (<32 weeks gestation) often need respiratory oxygen support, creating a hyperoxic environment.
- While hyperoxia is linked to lung and eye issues, its impact on skeletal muscle development is unclear.
- This study models premature infant oxygen therapy in rats to investigate skeletal muscle effects.
Purpose of the Study:
- To investigate the effects of early-life hyperoxia on skeletal muscle development in a rat model.
- To determine if postnatal hyperoxia exposure leads to muscle fiber atrophy or changes in fiber type.
Main Methods:
- Newborn rats were exposed to 80% oxygen from birth to postnatal day 12.
- Gastrocnemius muscles were analyzed at 12 weeks of age.
- Protein expression (Atrogin-1, adipophilin, myogenin) and myofiber size were assessed.
Main Results:
- Hyperoxia exposure significantly increased Atrogin-1 protein expression.
- Elevated levels of adipophilin, myogenic differentiation factor 1, and myogenin were observed.
- A significant reduction in gastrocnemius myofiber size was found in the hyperoxia group.
Conclusions:
- Transient hyperoxia during early life can hinder skeletal muscle development.
- These effects may persist into adulthood, suggesting long-term consequences.
- Hyperoxia exposure impedes muscle growth and may alter muscle characteristics.
Abstract:
Background/Objectives: Premature births below 32 weeks of gestation generally require respiratory oxygen support, leading to a relatively hyperoxic environment compared to in utero conditions. Transient hyperoxia exposure has been linked to an elevated risk of chronic lung disease and retinopathy of prematurity; however, its effects on skeletal muscles remain elusive. This study aimed to investigate the effects of hyperoxic exposure in rats as a model of premature infants receiving supplemental oxygen (30-60% O2 for several weeks). We hypothesized that rats exposed to postnatal hyperoxia would exhibit muscle fiber atrophy and alterations in fiber type. Methods: We used a rat model in which newborns were exposed to 80% oxygen from birth until postnatal day 12. We assessed the gastrocnemius muscles of rat legs at 12 weeks. Results: Rats exposed to hyperoxia showed substantially increased protein expression of Atrogin-1, along with elevated levels of adipophilin, myogenic differentiation factor 1, and myogenin. No significant changes were observed in the expression of slow or fast myosin heavy chain proteins. However, myofiber size in the gastrocnemius muscle was reduced in the hyperoxia-exposed group compared to the control group. Conclusions: Thus, transient hyperoxia exposure during early life can impede skeletal muscle development, potentially extending into adulthood.
