INVESTIGATION OF LIPID-PEROXIDATION IN LIPOSOMES INDUCED BY HEAVY-IONIRRADIATION

Lipid peroxidation induced by heavy ion irradiation was investigated i n 1,2-dilinoleoyl-sn-glycero-3-phosphocholine (DLPC) liposomes. Lipid peroxidation was induced using accelerated heavy ions that exhibit lin ear energy transfer (LET) values between 30 and 15 000 keV/mu m and do ses up to 100 kGy. With increasing LET, the formation of lipid peroxid ation products such as conjugated dienes, lipid hydroperoxides, and th iobarbituric acid-reactive substances decreased. When comparing differ ential absorption spectra and membrane fluidity following irradiation with heavy ions and x-rays (3 Gy/min), respectively, it is obvious tha t there are significant differences between the influences of densely and sparsely ionizing radiation on liposomal membranes. Indications fo r lipid fragmentation could be detected after heavy ion irradiation.