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Diaphragmatic activity is a determinant of postnatal lung growth

A L Mansell, J V Rojas, E M Sillos

    Journal of Applied Physiology (Bethesda, Md. : 1985)
    |September 1, 1986
    PubMed

    Insights

    Respiratory muscle activity influences lung growth. Unilateral diaphragmatic paralysis in cats and piglets led to increased growth in the contralateral lung, demonstrating regional control of lung parenchyma development.

    Area of Science:

    • Pulmonology
    • Developmental Biology
    • Physiology

    Background:

    • Lung growth and development are complex processes.
    • The role of mechanical forces, particularly from respiratory muscles, in regulating lung parenchyma growth is not fully understood.

    Purpose of the Study:

    • To investigate whether respiratory muscle activity dictates regional lung parenchyma growth.
    • To examine the effects of unilateral diaphragmatic paralysis on the growth of ipsilateral and contralateral lungs.

    Main Methods:

    • Unilateral diaphragmatic paralysis was surgically induced in juvenile cats and piglets via phrenectomy.
    • Lung growth was assessed by measuring wet lung weight, maximum inflation volume, and total protein content in contralateral and ipsilateral lungs.
    • Sham-operated animals served as controls.

    Main Results:

    • Phrenectomized animals showed significantly greater growth in the contralateral lung compared to the ipsilateral lung, indicated by higher ratios of wet lung weight, maximum inflation volume, and total protein content.
    • Overall functional residual capacity was reduced in phrenectomized cats.
    • Ratios of total protein to DNA and RNA to DNA remained unchanged, suggesting growth occurred via cell proliferation without altered cell composition.

    Conclusions:

    • Regional lung parenchyma growth, driven by cell proliferation, is partly dependent on the regional distribution of respiratory muscle activity.
    • Mechanical forces generated by respiratory muscles play a crucial role in regulating lung development.

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