AJP - Gastrointestinal and Liver Physiology, Vol 264, Issue 5 835-G839, Copyright © 1993 by American Physiological Society
Protection against hydrophobic bile salt-induced cell membrane damage by liposomes and hydrophilic bile salts
H. Sagawa, S. Tazuma and G. Kajiyama
First Department of Internal Medicine, Hiroshima University School of Medicine, Japan.
Under physiological circumstances, cell membrane damage is not evident in
biliary systems, despite the fact that hydrophobic bile salts are known to
induce such damage by their detergent effects. The aim of this study was to
determine the cytoprotective effects of liposomes and hydrophilic bile
salts against hydrophobic bile salt-induced cell membrane damage, with the
use of hemolysis of erythrocytes as a model of cytotoxicity. Washed human
erythrocytes were incubated for 10, 30, 60, 90, and 120 min in buffered
media (pH 7.45) containing increasing concentrations of different bile
salts (1, 2.5, 5, 25, 50 mM). The cytotoxicity of the bile salts was found
to be dose and time dependent and was correlated to the degree of the
hydrophobicity of the bile salts as determined by the retention factor in
reversed-phase high-performance liquid chromatography. Hydrophobic bile
salt-induced hemolysis was reduced by liposomes and hydrophilic bile salts.
Cytoprotection by liposomes was related to the degree of saturation of the
fatty acyl chains, and cytoprotection by hydrophilic bile salts was related
to their hydrophilicity. These in vitro findings indicate that vesicles may
play a role in protection against cell membrane damage by hydrophobic bile
salts in biliary systems and that such damage may be caused by an imbalance
between hydrophobic and hydrophilic bile salts.
