Flexibility of microstructural adaptations in airway smooth muscle
| Autor: | Alexis Dufour-Mailhot, Cyndi Henry, Magali Boucher, Marie-Annick Clavel, Sophie Tremblay-Pitre, Marine Clisson, Fatemeh Khadangi, Ynuk Bossé, Jonathan Beaudoin |
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| Rok vydání: | 2021 |
| Předmět: |
0301 basic medicine
Sustained contraction Flexibility (anatomy) Materials science Physiology Strain (injury) Elastance 03 medical and health sciences 0302 clinical medicine Physiology (medical) medicine Animals Tissue mechanics Tidal volume Sheep Airway Resistance Respiration Muscle Smooth Airway smooth muscle medicine.disease Adaptation Physiological Trachea 030104 developmental biology medicine.anatomical_structure Inhalation Breathing Biophysics 030217 neurology & neurosurgery Muscle Contraction |
| Zdroj: | Journal of Applied Physiology. 130:1555-1561 |
| ISSN: | 1522-1601 8750-7587 |
| Popis: | The airway smooth muscle undergoes an elastic transition during a sustained contraction, characterized by a gradual decrease in hysteresivity caused by a relatively greater rate of increase in elastance than resistance. We recently demonstrated that these mechanical changes are more likely to persist after a large strain when they are acquired in dynamic versus static conditions; as if the microstructural adaptations liable for the elastic transition are more flexible when they evolve in dynamic conditions. The extent of this flexibility is undefined. Herein, contracted ovine tracheal smooth muscle strips were kept in dynamic conditions simulating tidal breathing (sinusoidal length oscillations at 5% amplitude) and then subjected to simulated deep inspirations (DI). Each DI was straining the muscle by either 10%, 20%, or 30% and was imposed at either 2, 5, 10, or 30 min after the preceding DI. The goal was to assess whether and the extent by which the time-dependent decrease in hysteresivity is preserved following the DI. The results show that the time-dependent decrease in hysteresivity seen pre-DI was preserved after a strain of 10%, but not after a strain of 20% or 30%. This suggests that the microstructural adaptations liable for the elastic transition withstood a strain at least twofold greater than the oscillating strain that pertained during their evolution (10% vs. 5%). We propose that a muscle adapting in dynamic conditions forges microstructures exhibiting a substantial degree of flexibility. |
| Databáze: | OpenAIRE |
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