Panzner E A, Jansons V K
J Cancer Res Clin Oncol. 1979 Sep;95(1):29-37. doi: 10.1007/BF00411106.
The parameters which influence the in vitro cytotoxicity of positively charged liposomes for L 1210 cells were analyzed. The cytotoxicity was liposome/cell ratio-dependent. It also depended upon the mole fractions of stearylamine (SA) to phosphatidylcholine (PC). There was no difference between the cytotoxicity of unilamellar and multilamellar vesicles but the cytotoxic effect of free SA was about 4 times greater than that of liposome incorporated SA at a molar ratio of 1:4, SA:PC, respectively. The process which resulted in cell death was irreversible after 60 min of cell-liposome contact. The simultaneous presence of neutral liposomes or of positively charged liposomes with a lesser charge density decreased the cytotoxic effect of liposomes with a higher SA content. The cytotoxicity could be decreased by trypsinization of cells following exposure to liposomes while treatment of cells with trypsin prior to the exposure to positively charged liposomes had no effect on the subsequent cytotoxicity. The cytotoxicity was also decreased if cells were incubated in the presence of sodium azide. The usual concentration of serum (10%) present in the growth medium had no effect on the cytotoxicity while preincubation of cells with liposomes in 80% serum resulted in full protection. The protective effect of serum could be replaced by the albumin fraction.
分析了影响带正电荷脂质体对L 1210细胞体外细胞毒性的参数。细胞毒性取决于脂质体/细胞比例。它还取决于硬脂胺（SA）与磷脂酰胆碱（PC）的摩尔分数。单层囊泡和多层囊泡的细胞毒性没有差异，但游离SA的细胞毒性在SA:PC摩尔比为1:4时比脂质体包封的SA大约4倍。细胞与脂质体接触60分钟后导致细胞死亡的过程是不可逆的。中性脂质体或电荷密度较低的带正电荷脂质体的同时存在会降低SA含量较高的脂质体的细胞毒性。暴露于脂质体后用胰蛋白酶处理细胞可降低细胞毒性，而在暴露于带正电荷脂质体之前用胰蛋白酶处理细胞对随后的细胞毒性没有影响。如果在叠氮化钠存在下孵育细胞，细胞毒性也会降低。生长培养基中通常存在的血清浓度（10%）对细胞毒性没有影响，而在80%血清中用脂质体预孵育细胞可提供完全保护。血清的保护作用可以被白蛋白部分替代。
