Cationic Liposome-induced Oxidative Stress And DNA Damage In Cells

As an important gene and drug carrier,the synthetic cationic liposome has many advantages.However,the mechanism of its toxic effect on cells is still unclear,which seriously affects its clinical application.In this paper,we investigated whether cationic liposomes induce oxidative stress in cells and lead to cytotoxicity.In this paper,the three kinds of lipids of our research group independently developed and synthesized:N,N-bis-decanethoxamide ethyl trimeric ornithine amide with tripeptide head(CDO14)and N,N-bis-decanethoxamide ethyl-N,N-dimethyl ammonium iodide with mono quarterly ammonium salt head(CDA14)and 1,2-bis-[N-tetradecanoxamide ethyl-N,N-dimethyl ammonium iodide]ethane with diquaternary ammonium salt head(CTA14).CDO14,CDA14 and CTA14 cationic liposomes were prepared by thin film dispersion and ultrasonic dispersion.Zeta potential,particle size and morphology of the liposomes were characterized by nanometer particle size meter and transmission electron microscope.The results showed that the average Zeta potential of CDO14 was 65 m V,CDA14 was 81 m V and CTA14 was 84 m V,which were basically spherical in shape and had an average particle size of about 150 nm.Human lung cancer cells(NCI-H460)and human embryonic lung normal cells(MRC-5)were selected.CCK-8 method,morphological observation of reactive oxygen species(ROS)fluorescence labeling,quantitative determination by flow cytometry,free radical detection of reactive oxygen species and single-cell gel electrophoresis were used.The cytotoxic mechanisms of cationic liposomes with different head structures,identical bonding linkers and hydrophobic tails were compared.The results showed that reactive oxygen species free radical content induced by cationic liposomes such as superoxide,hydrogen peroxide(H₂O₂),hydroxyl radical(·OH),nitric oxide(NO)and malondialdehyde(MDA)were positively correlated with the dose.Among them,the difference between CDA14 and CTA14 groups with high concentrations(0.1?M and 0.2?M)and those with low concentration(0.05?Mand the blank control group was very significant,however,CDO14 only showed significant difference in 0.2?M,and the oxidative stress damage value of three liposomes to NCI-H460cells was higher than that of MRC-5 cells.Therefore,the oxidative stress damage caused by liposome CDO14 wit the peptide head was far less than that caused by liposome CDA14 with the single quaternary ammonium salt head,and CDA14 was smaller than CTA14with the head of double quaternary ammonium salt.The damage degree of DNA induced by three cationic liposomes was further determined by single cell gel electrophoresis.The results showed that the DNA damage caused by oxidative stress generated by CDO14 was far less than that caused by CDA14,however,CDA14 was smaller than CTA14.In summary,cationic liposome-induced cellular oxidative stress and DNA damage are closely related to head structure and dose.This study provides a scientific reference for the biosafety of cationic liposomes and the design of new cationic liposomes.