TY - JOUR
T1 - Oxidative stress effect on the integrity of lipid bilayers is modulated by cholesterol level of bilayers
AU - Tirosh, Oren
AU - Kohen, Ron
AU - Katzhendler, Jehoshua
AU - Alon, Anat
AU - Barenholz, Yechezkel
N1 - Funding Information:
This work was supported in part by The Israel-United States Science Foundation, BSF 95/318 to Y.B.
PY - 1997
Y1 - 1997
N2 - Large unilamellar vesicles (120-160 nm) composed of egg phosphatidylcholine (egg PC) containing approximately 22 wt% of polyunsaturated fatty acids (PUFA) and various mol% (0, 10, 22, or 45) of cholesterol were exposed to oxidative stress. The hydrophilic azo compound 2,2'-azobis-(2-amidinopropane)2HCl (AAPH) which was thermally decomposed to produce a constant flux of peroxy radicals was the source of the oxidative stress (≤ 48 h incubation at 37°C). Cholesterol loss following the oxidation was up to 33%, while PUFA were more extensively damaged; loss was up to 52, 88, and 100% for C-18:2, C-20:4, and C-22:6, respectively. (ii) Oxidizability of cholesterol when quantified in absolute amount was three-fold higher when its level was 45 mol%. The interrelationship between bilayer structure, especially its lateral organization and free volume, and lipid peroxidation are discussed. Differential scanning calorimetry of oxidized multilamellar vesicles lacking cholesterol revealed that a high level of oxidative damage to egg phosphatidylcholine PUFA resulted in the loss of the gel to liquid-crystalline phase transition of egg PC (broad peak at around -8°C).
AB - Large unilamellar vesicles (120-160 nm) composed of egg phosphatidylcholine (egg PC) containing approximately 22 wt% of polyunsaturated fatty acids (PUFA) and various mol% (0, 10, 22, or 45) of cholesterol were exposed to oxidative stress. The hydrophilic azo compound 2,2'-azobis-(2-amidinopropane)2HCl (AAPH) which was thermally decomposed to produce a constant flux of peroxy radicals was the source of the oxidative stress (≤ 48 h incubation at 37°C). Cholesterol loss following the oxidation was up to 33%, while PUFA were more extensively damaged; loss was up to 52, 88, and 100% for C-18:2, C-20:4, and C-22:6, respectively. (ii) Oxidizability of cholesterol when quantified in absolute amount was three-fold higher when its level was 45 mol%. The interrelationship between bilayer structure, especially its lateral organization and free volume, and lipid peroxidation are discussed. Differential scanning calorimetry of oxidized multilamellar vesicles lacking cholesterol revealed that a high level of oxidative damage to egg phosphatidylcholine PUFA resulted in the loss of the gel to liquid-crystalline phase transition of egg PC (broad peak at around -8°C).
KW - Acyl chains
KW - Cholesterol
KW - Lipid peroxidation
KW - Liposomes
UR - http://www.scopus.com/inward/record.url?scp=0030856997&partnerID=8YFLogxK
U2 - 10.1016/S0009-3084(97)00019-4
DO - 10.1016/S0009-3084(97)00019-4
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C2 - 9219345
AN - SCOPUS:0030856997
SN - 0009-3084
VL - 87
SP - 17
EP - 22
JO - Chemistry and Physics of Lipids
JF - Chemistry and Physics of Lipids
IS - 1
ER -