title: Functional silica nanoparticle-mediated neuronal membrane sealing following traumatic spinal cord injury.
abstract: The mechanical damage to neurons and their processes induced by spinal cord injury (SCI) causes a progressive cascade of pathophysiological events beginning with the derangement of ionic equilibrium and collapse of membrane permeability. This leads to a cumulative deterioration of neurons, axons, and the tissue architecture of the cord. We have previously shown that the application of the hydrophilic polymer polyethylene glycol (PEG) following spinal cord or brain injury can rapidly restore membrane integrity, reduce oxidative stress, restore impaired axonal conductivity, and mediate functional recovery in rats, guinea pigs, and dogs. However there are limits to both the concentration and the molecular weight of the application that do not permit the broadest recovery across an injured animal population. In this study, PEG-decorated silica nanoparticles (PSiNPs) sealed cells, as shown by the significantly reduced leakage of lactate dehydrogenase from damaged cells compared with uncoated particles or PEG alone. Further in vivo tests showed that PSiNPs also significantly reduced the formation of reactive oxygen species and the process of lipid peroxidation of the membrane. Fabrication of PSiNPs containing embedded dyes also revealed targeting of the particles to damaged, but not undamaged, spinal cord tissues. In an in vivo crush/contusion model of guinea pig SCI, every animal but one injected with PSiNPs recovered conduction through the cord lesion, whereas none of the control animals did. These findings suggest that the use of multifunctional nanoparticles may offer a novel treatment approach for spinal cord injury, traumatic brain injury, and possibly neurodegenerative disorders.
authors.affiliation: Center for Paralysis Research, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Youngnam
authors.initials: Y
authors.lastname: Cho
authors.forename: Riyi
authors.initials: R
authors.lastname: Shi
authors.forename: Albena
authors.initials: A
authors.lastname: Ivanisevic
authors.forename: Richard Ben
authors.initials: RB
authors.lastname: Borgens
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000187:drug effects* / Q000502:physiology; D004195:Disease Models, Animal; D016503:Drug Delivery Systems; D005260:Female; D006168:Guinea Pigs; D007770:L-Lactate Dehydrogenase / Q000032:analysis / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects / Q000502:physiology; D053758:Nanoparticles / Q000737:chemistry / Q000627:therapeutic use*; D009410:Nerve Degeneration / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D019635:Neurosurgical Procedures / Q000379:methods; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D011092:Polyethylene Glycols / Q000494:pharmacology* / Q000627:therapeutic use; D020127:Recovery of Function / Q000187:drug effects / Q000502:physiology; D012822:Silicon Dioxide / Q000737:chemistry / Q000627:therapeutic use*; D013119:Spinal Cord Injuries / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D016896:Treatment Outcome
chemical_list: D011092:Polyethylene Glycols; D012822:Silicon Dioxide; D007770:L-Lactate Dehydrogenase