【作者】 王薇； 熊微； 万江陵； 徐辉碧； 杨祥良；

【Author】 WANG Wei 1, XIONG Wei 1, WAN Jiangling 1, XU Huibi 2, YANG Xiangliang1 (1. College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China; 2. Department of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China)

【机构】 华中科技大学生科院药物所； 华中科技大学化学系；

【摘要】 目的:为制备低毒性的树状大分子,用聚乙二醇(PEG)对聚酰胺-胺(PAMAM)树状大分子进行修饰,并考察PEG化对胞内活性氧(ROS)产生的影响。方法:用两种分子量的PEG经两种取代度修饰PAMAM树状大分子,对合成的化合物进行了表征,考察了细胞对化合物的摄取能力,化合物的转染效率,用MTT法考察了细胞毒性,并研究了化合物引发胞内活性氧的产生、线粒体膜电位的变化,以及诱发细胞凋亡的能力。结果:PEG修饰后基本不影响细胞对树状大分子的摄取,并保有一定的转染效率。PEG化可以显著降低PAMAM的细胞毒性,降低毒性的能力随PEG的分子量和修饰度的增大而明显加强。PEG修饰对PAMAM引发的细胞凋亡有明显的抑制作用,显著降低胞内ROS含量,并保护线粒体膜电位的稳定。结论:PEG修饰通过减少胞内ROS的产生来降低PAMAM的细胞毒性,高修饰度有明显的降低毒性的作用。更多还原

【Abstract】 Due to its unique structure, poly (amidoamine) (PAMAM) dendrimer has been widely used in medical applications. However, the PAMAM dendrimers bearing amine terminals show certain cytotoxicity. In order to improve the biocompatibility, we modified the generation 5 PAMAM dendrimers by conjugating with the poly (ethylene glycol) (PEG) of two different molecular weights and different number of chains. The IC50 values of PEGylated dendrimers were from 12 to 105 fold higher compared with the value of the PAMAM dendrimers. To elucidate why PEGylation could decrease the cytotoxicity, the intracellular responses, reactive oxygen species (ROS) content, the mitochondrial membrane potential (MMP) and the apoptosis, were examined. The results indicated that conjugated with PEG could effectively reduce the PAMAM-induced cell apoptosis by attenuation of ROS production and inhibition of PAMAM-induced MMP collapse. Treated with α-tocopherol, the cell viability increased in PEGylated groups but did not change in PAMAM group, which confirmed that PEGylation inhibited PAMAM dendrimers-induced cytotoxicity by attenuation of oxidative stress. Meanwhile, the dendrimers conjugated with less PEG chains did not significantly change the endocytic properties; furthermore, the PEGylated ones exhibited certain transfection efficiency. The dendrimers with higher molecular weight and more PEG chains were much less cytotoxic. This study provides a novel insight into the effects of PEGylation on the decrease of cytotoxicity at the molecular level.更多还原