Shadyro O I, Yurkova I L, Kisel M A
Department of Chemistry of the Belarussian State University, Skaryna av., 4, 220050 Minsk, Republic of Belarus.
Int J Radiat Biol. 2002 Mar;78(3):211-7. doi: 10.1080/09553000110104065.
To ascertain the possibility of fragmentation processes in lipid membranes when acted upon with gamma-radiation under various conditions, and to evaluate fragmentation processes quantitatively in comparison with the lipid peroxidation processes.
Phospholipids as components of multilamellar liposomes exposed to 137Cs gamma-rays at dose-rates of 0.06 and 0.33 Gy s-1 in the dose range 0-18 kGy. Peroxidation products were determined spectrophotometrically and fragmentation products were analysed using thin-layer chromatography and GLC methods.
Phosphatidylglycerol containing unsaturated fatty acid residues and free hydroxyl groups underwent both peroxidation and fragmentation when its aqueous dispersions were treated with ionizing radiation. gamma-Radiolysis of multilamellar liposomes led to the formation of peroxidation products, as well as phosphatidic acid and hydroxyacetone, fragmentation products of the initial lipid. Comparable radiation-chemical yields of conjugated-diene products and phosphatidic acid indicate that the probabilities of oxidation and fragmentation processes to occur are approximately equal in this case. In contrast to lipid peroxidation, lipid fragmentation is not accelerated but suppressed by oxygen and appears to be a prevailing process in de-aerated solutions. The phosphatidic acid formed as a result of phosphatidylglycerol fragmentation can intensify the lipid peroxidation.
Treatment of lipid membranes with ionizing radiation leads to the destructive processes within both hydrophobic and hydrophilic moiety of lipids.
确定在各种条件下用γ射线辐照时脂质膜中发生碎片化过程的可能性，并与脂质过氧化过程相比对碎片化过程进行定量评估。
作为多层脂质体成分的磷脂，在0 - 18 kGy的剂量范围内，以0.06和0.33 Gy s-1的剂量率暴露于137Csγ射线下。通过分光光度法测定过氧化产物，并使用薄层色谱法和气相色谱法分析碎片化产物。
含有不饱和脂肪酸残基和游离羟基的磷脂酰甘油在其水分散体用电离辐射处理时会发生过氧化和碎片化。多层脂质体的γ辐解导致过氧化产物以及初始脂质的碎片化产物磷脂酸和羟基丙酮的形成。共轭二烯产物和磷脂酸的可比辐射化学产率表明，在这种情况下氧化和碎片化过程发生的概率大致相等。与脂质过氧化相反，脂质碎片化不会被氧气加速反而会被抑制，并且似乎是在脱气溶液中的主要过程。磷脂酰甘油碎片化产生的磷脂酸可加剧脂质过氧化。
用电离辐射处理脂质膜会导致脂质的疏水和亲水部分都发生破坏过程。
