Abstract
We investigated the effect of the cytoskeletal prestress (P) on the elastic and frictional properties of cultured human airway smooth muscle cells during oscillatory loading; P is preexisting tensile stress in the actin cytoskeleton generated by the cell contractile apparatus. We oscillated (0.1 Hz, 6 Pa peak to peak) small ferromagnetic beads bound to integrin receptors and computed the storage (elastic) modulus (G′) and the loss (frictional) modulus (G″) from the applied torque and the corresponding bead rotation. All measurements were done at baseline and after cells were treated with graded doses of either histamine (0.1, 1, 10 μM) or isoproterenol (0.01, 0.1, 1, 10 μM). Values for P for these concentrations were taken from a previous study (Wang et al., Am J Physiol Cell Physiol, in press). It was found that G′ and G″, as well as P, increased/decreased with increasing doses of histamine/isoproterenol. Both G′ and G″ exhibited linear dependences on P: G′(Pa) = 0.20P + 82 and G″(Pa) = 0.05P + 32. The dependence of G′ on P is consistent with our previous findings and with the behavior of stress-supported structures. The dependence of G″ on P is a novel finding. It could be attributed to a variety of mechanisms. Some of those mechanisms are discussed in detail. We concluded that, in addition to the central mechanisms by which stress-supported structures develop mechanical stresses, other mechanisms might need to be invoked to fully explain the observed dependence of the cell mechanical properties on the state of cell contractility.
Original language | English (US) |
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Pages (from-to) | 1443-1450 |
Number of pages | 8 |
Journal | Journal of Applied Physiology |
Volume | 92 |
Issue number | 4 |
DOIs | |
State | Published - 2002 |
Externally published | Yes |
Keywords
- Actin network
- Cytoskeletal mechanics
- Loss modulus
- Oscillatory cytometry
- Storage modulus
ASJC Scopus subject areas
- Physiology
- Endocrinology
- Orthopedics and Sports Medicine
- Physical Therapy, Sports Therapy and Rehabilitation