title: Inhibitory effects of trolox-encapsulated chitosan nanoparticles on tert-butylhydroperoxide induced RAW264.7 apoptosis.
abstract: A nanocarrier, namely, hydroxylethyl-chitosan nanoparticles was developed in this research for delivering antioxidants with 6-hydroxy-2, 5, 7, 8-tetra-methylchromane-2-carboxylic acid (trolox) as a model antioxidant. The trolox-encapsulated chitosan nanoparticles (trolox-CS NPs) were prepared by modifying chitosan with epoxyethane, which self-assembled into NPs and entrapped trolox, and then characterized by their size, size distribution, morphology and in vitro trolox release profile. Intracellular trafficking of CS NPs was observed. The anti-oxidant effect and potential mechanism of trolox-CS NPs were subsequently investigated in RAW264.7 cells. The effects of trolox-CS NPs on RAW264.7 cells damaged by tert-butylhydroperoxide (t-BHP) were determined by MTT assay for cell viability, MDA assay for membrane lipid peroxidation, JC-1 probe and Annexin V-FITC/PI double staining for mitochondria membrane potential (MMP) and RAW264.7 apoptosis, respectively. The trolox-CS NPs significantly improved cell viability and reduced MDA content compared with those of cells treated with free trolox. The trolox-CS NPs treatment inhibited MMP collapse and RAW264.7 apoptosis more obviously than free trolox. Molecular basis of apoptosis studied by western blotting revealed that trolox-CS NPs may block mitochondria-mediated apoptosis pathway through up-regulation of Bcl-2 and down-regulation of Bax and inhibiting the activation of pro-caspase 3, PARP and Bid.
authors.affiliation: State Key Lab for Structural Chemistry of Unstable and Stable Species, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China.
authors.forename: Lu
authors.initials: L
authors.lastname: Han
authors.forename: Li-Bo
authors.initials: LB
authors.lastname: Du
authors.forename: Anil
authors.initials: A
authors.lastname: Kumar
authors.forename: Hong-Ying
authors.initials: HY
authors.lastname: Jia
authors.forename: Xing-Jie
authors.initials: XJ
authors.lastname: Liang
authors.forename: Qiu
authors.initials: Q
authors.lastname: Tian
authors.forename: Guang-Jun
authors.initials: GJ
authors.lastname: Nie
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D048271:Chitosan / Q000737:chemistry*; D002839:Chromans / Q000737:chemistry*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D053758:Nanoparticles / Q000737:chemistry*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D020122:tert-Butylhydroperoxide / Q000494:pharmacology*
chemical_list: D002839:Chromans; D019253:Proto-Oncogene Proteins c-bcl-2; D048271:Chitosan; D020122:tert-Butylhydroperoxide; C010643:6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid