Measurement of membrane hydraulic conductivity of bovine carotid artery endothelial cells using a perfusion microscope.

The osmotic properties of bovine carotid artery endothelial cells (BCAECs) associated with cryobiology were investigated using a perfusion microscope. These properties include the hydraulic conductivity (Lp) and its activation energy (ELp). The response of isolated cells was observed when the extracellular concentration increased from 0.15 M to 0.5 M NaCl at three different temperatures. The transient volumes of the cell were calculated from the measurements of the projected areas with an assumption of a spherical cell. The hydraulic conductivity (Lp) and the osmotically inactive volume (Vb) of BCAECs were simultaneously determined using nonlinear regression to fit the change of cell volume estimated by water transport equations to measured cell volumes. The Lp values were 0.26 +/- 0.08, 0.12 +/- 0.02, and 0.06 +/- 0.02 m/atm/min (mean +/- SD) at 23, 11 and 4 degree C, respectively, yielding the activation energy of Lp of 47.6 kJ/mol according to the Arrhenius relationship.