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Lubrication regimes in mesothelial sliding
Stephen H Loring1, Richard E Brown, Andrew Gouldstone
1Department of Anesthesia and Critical Care, Beth Israel Deaconess Medical Center and Harvard Medical School, DA 717, 330 Brookline Avenue, Boston, MA 02215-5491, USA. sloring@bidmc.harvard.edu
Journal of Biomechanics
|October 11, 2005
Summary
Mesothelial surfaces in the body are protected by hydrodynamic pressure, which increases separation during organ sliding. This lubrication mechanism prevents excessive shear forces, ensuring normal organ function.
Area of Science:
- Biophysics
- Physiology
- Tribology
Background:
- Organs like the lungs and heart must change shape and slide against body walls for normal function.
- The role of mesothelial surfaces and lubricating fluid in preventing friction during this sliding is not fully understood.
Purpose of the Study:
- To investigate whether mesothelial surfaces maintain contact or are separated by hydrodynamic pressure during sliding.
- To measure the coefficient of friction (μ) of mesothelial surfaces under physiological conditions.
Main Methods:
- The coefficient of friction (μ) of rat abdominal wall mesothelium sliding on glass in saline was measured.
- Experiments were conducted at physiological velocities (0.0123–6.14 cm/s) and normal stresses (50–200 Pa).
Main Results:
- Friction (μ) varied significantly with sliding velocity (P<0.001).
- A mixed lubrication regime was observed, with friction decreasing at intermediate speeds and increasing at higher speeds.
- Hydrodynamic pressure appears to partially separate the mesothelial surfaces.
Conclusions:
- Mesothelial surfaces sliding under physiological conditions are protected from excessive shear by hydrodynamic pressures.
- Increased separation of surfaces due to hydrodynamic pressure is a key lubrication mechanism for internal organs.