铝离子对二价铁离子启动的卵磷脂脂质体脂质过氧化的影响

THE EFFECT OF ALUMINUM IONS ON THE Fe2+-INITIATED LIPID PEROXIDATION

利用化学发光、ＴＢＡ 反应与测量共轭二烯的方法观测了Ａｌ３ ＋ 对Ｆｅ２ ＋ 启动的卵磷脂脂质体脂质过氧化的影响。实验结果显示，在生理ｐＨ 条件下，Ａｌ３ ＋ 对Ｆｅ２ ＋ 启动的脂质过氧化有增强作用，表现为缩短潜伏期和加快脂质过氧化的反应速率， Ａｌ３ ＋ 的增强作用与脂质体中原先存在的过氧化物有关。这可能是因为在脂质体存在的条件下，Ａｌ３ ＋ 加速了Ｆｅ２ ＋ 的氧化，且加速作用与脂质体中原先存在的过氧化物的含量有关；另一方面，Ａｌ３ ＋ 可以引起脂质体的聚集，表现为浊度的增加；测量脂质体上标记的脂肪酸自旋标记物５ － Ｄｏｘｙｌ ｓｔｅａｒｉｃ ａｃｉｄ 的ＥＳＲ 波谱发现： Ａｌ３ ＋ 降低了脂质体的膜脂的流动性。研究表明： Ａｌ３ ＋ 对Ｆｅ２ ＋ 启动的卵磷脂脂质体的过氧化的增强作用可能与Ａｌ３ ＋ 加速了Ｆｅ２ ＋

The effect of aluminum ions on the Fe2+-initiated lipid peroxidation in liposomes was studied by chemiluminescence, TBARS, conjugate dienes assays and ESR spectroscopy. The results showed that Al3+ could enhance the lipid peroxidation by increase the reaction rate and shorten the latent period in lipid peroxidation. Both the increase of lipid peroxidation reaction rate and the shortening of the latent period were dependent on the pre-existed lipid peroxides in liposomes. Al3+ accelerated the oxidation of Fe2+ in liposomal system only when liposomes contain pre-exist peroxides. The addition of Al3+ to the liposomal suspension resulted in a marked increase of turbidity of the suspension and decrease of fluidity of the liposomes. The study revealed that the enhancement of Fe2+-initiated lipid peroxidation by Al3+ may be due to the acceleration of Fe2+ oxidation and the change on the physical state of liposomal membrane induced by Al3+.