辐射对磷脂和脂质体的过氧化损伤研究

【作者】 王宁；

【导师】 秦广雍； 王卫东；

【作者基本信息】 郑州大学 ， 生物物理， 2007， 硕士

【摘要】 生物膜具有很重要的生物学功能，膜的破坏将会影响到细胞内生物活性分子的转移和膜结合酶的活性，从而严重干扰代谢的方向性、有序性和协调性，进而导致细胞的死亡。辐射生物学研究表明，生物膜是仅次于DNA的辐射损伤的靶，对辐射非常敏感。已有的研究表明生物膜的辐射损伤主要是生物膜中的不饱和脂肪酸受到辐射后，不饱和脂肪酸的过氧化反应而造成的。而近年来，随着臭氧层的破坏和空气污染的增加，到达地球表面的各种射线逐渐增加，这将会对地球表面的生物造成很大程度的影响。因此，本实验选择紫外线和γ射线对生物膜进行辐照，初步探讨了这两种射线对脂质体的过氧化损伤机制和胆固醇对过氧化损伤的保护机制，结果表明：(1)随着照射量以及磷脂和脂质体浓度的增加其过氧化产物(MDA)也随之增加；在相同紫外线照射剂量的前提下，随着实验材料浓度的增加，过氧化产物的增幅基本相等(略呈减小)。但是，随着实验样品浓度的增加，单位摩尔浓度的样品所产生的MDA的量呈减小态势。(2)在实验样品中加入胆固醇后，含有胆固醇的脂质体的过氧化产物明显减小，而含有胆固醇的磷脂的过氧化产物却差别不大。这可能和胆固醇与磷脂分子结合的方式有关系，也就是说当胆固醇和磷脂分子以一定形式结合起来的时候才会对过氧化损伤起到抑制作用。(3)通过对磷脂氧化产物中的共轭二烯(dienen conjugate)的检测看，共轭二烯的量也是随着射线照射量的增加而增大的，并且基本上是和照射量呈线性增加。当脂质体的浓度减小时，共轭二烯的量剧减，说明共轭二烯的形成和脂质体的浓度有很大的关系。在脂质体中加入胆固醇后共轭二烯的量也是下降很快。说明在脂质体发生氧化的时候胆固醇对产物共轭二烯也有很好的抑制作用。由此可以说明胆固醇对由射线引起的脂质体的过氧化损伤起到了很好的保护作用。(4)紫外线和γ射线对样品的辐射损伤差别不大。更多还原

【Abstract】 Liposome membrane has the very important biology function, existing the very close relation with the DNA replication. Membrane damage will affect the transfer of intracellular molecular biological activity and membrane enzyme activity, This will seriously interfere with the metabolism of direction, orderly and coordination, which led to cell death. Radiation biology research showed that Liposome membrane is a very important target to radiation except DNA, is very sensitive to radiation. Several studies have demonstrated liposome membrane of radiation injury is the liposome membrane of unsaturated fatty acid oxidation caused by the reaction. And in recent years, with the destruction of the ozone layer and air pollution, reached the Earth’s surface ray gradually increase, This will be on the surface of the Earth caused great impacts. Therefore, I choose UV andγ-ray irradiation to the liposome membrane. Preliminary discussion of injury mechanism of the ray to liposome oxidation and the protective mechanism of cholesterol to oxidation damage. Our results show:(1) With the increase of irradiation dose and the concentration of the test sample, its peroxidation products (MDA) have also increased. The same dose of UV irradiation on the premise, with the concentration of experimental materials increased, peroxidation product growth is basically the same (slightly reduced). However, as the concentration of experimental samples increased, unit molar concentration of the sample by the amount of MDA was reduced;(2) With the addition of cholesterol to experimental samples, cholesterol containing liposomes peroxidation products decreased, cholesterol containing phospholipid peroxidation product but the difference was not significant. This might be related to the way cholesterol and phospholipid molecules combined. To inhibition the peroxidation injury cholesterol and phospholipid molecules should combined in a right form;(3) By testing the product of phospholipid oxidation of diene conjugated, With the irradiation dose increased diene conjugated is also increased and basically exposure and increased linearly. When liposome concentration decreased, the total amount of diene conjugated dramatic reduction , this demonstrated that diene conjugated formation is related to the concentration of liposomes after adding cholesterol to Liposomes, the volume of diene conjugate is declining rapidly. So, Cholesterol to ray-induced oxidative damage have good protection.(4) the difference of peroxidation damage betweenΓ-ray and UV irradiation is not so notable.更多还原