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Rheological behavior of rat mesangial cells during swelling in vitro
W Craelius1, C J Huang, H Guber
1Department of Biomedical Engineering, Rutgers University, Piscataway, NJ 08854, USA. craelius@rci.rutgers.edu
Biorheology
|June 26, 1998
Summary
Rat mesangial cells exhibit viscoelastic properties, with swelling triggering a significant potassium efflux essential for volume regulation. This swelling-induced ion transport is crucial for cell survival.
Area of Science:
- Cellular mechanics
- Biophysics
- Physiology
Background:
- Cellular response to mechanical forces is dictated by membrane and cytoplasmic rheology.
- Understanding these properties is key to cell mechanics and function.
Purpose of the Study:
- To characterize the rheological properties of rat mesangial cells (MC).
- To investigate the mechanical and electrical responses of MC to swelling.
- To elucidate the role of ion transport in cell volume regulation.
Main Methods:
- Electrophysiologic techniques (whole-cell recording) were used to measure ion transport rates during hyposmotic exposure.
- Video microscopic techniques were employed to measure cell swelling in response to pressure and osmotic changes.
- Mechanical and electrical responses were analyzed to determine viscoelastic properties.
Main Results:
- Cell swelling demonstrated a nonlinear relationship with internal pressure, indicative of a viscoelastic cytoplasm.
- Swelling rapidly induced an outwardly rectifying membrane conductance, significantly increasing baseline conductance.
- Swelling-induced current was K+-selective, partially reversible, and antagonized by GdCl3, with GdCl3 treatment leading to cell lysis.
Conclusions:
- Cell volume regulation in MC relies on substantial swelling-induced potassium efflux.
- Cell swelling in MC is a viscoelastic process influenced by cytoplasmic viscosity.
- These findings highlight the interplay between mechanical forces, ion transport, and cell volume homeostasis.