title: Elevated axonal membrane permeability and its correlation with motor deficits in an animal model of multiple sclerosis.
abstract: BACKGROUND
  It is increasingly clear that in addition to myelin disruption, axonal degeneration may also represent a key pathology in multiple sclerosis (MS). Hence, elucidating the mechanisms of axonal degeneration may not only enhance our understanding of the overall MS pathology, but also elucidate additional therapeutic targets. The objective of this study is assess the degree of axonal membrane disruption and its significance in motor deficits in EAE mice.
  
  
  METHODS
  Experimental Autoimmune Encephalomyelitis was induced in mice by subcutaneous injection of myelin oligodendrocyte glycoprotein/complete Freud's adjuvant emulsion, followed by two intraperitoneal injections of pertussis toxin. Behavioral assessment was performed using a 5-point scale. Horseradish Peroxidase Exclusion test was used to quantify the disruption of axonal membrane. Polyethylene glycol was prepared as a 30% (w/v) solution in phosphate buffered saline and injected intraperitoneally.
  
  
  RESULTS
  We have found evidence of axonal membrane disruption in EAE mice when symptoms peak and to a lesser degree, in the pre-symptomatic stage of EAE mice. Furthermore, polyethylene glycol (PEG), a known membrane fusogen, significantly reduces axonal membrane disruption in EAE mice. Such PEG-mediated membrane repair was accompanied by significant amelioration of behavioral deficits, including a delay in the emergence of motor deficits, a delay of the emergence of peak symptom, and a reduction in the severity of peak symptom.
  
  
  CONCLUSIONS
  The current study is the first indication that axonal membrane disruption may be an important part of the pathology in EAE mice and may underlies behavioral deficits. Our study also presents the initial observation that PEG may be a therapeutic agent that can repair axolemma, arrest axonal degeneration and reduce motor deficits in EAE mice.
authors.affiliation: Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907 USA.
authors.forename: Gary
authors.initials: G
authors.lastname: Leung
authors.affiliation: Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907 USA.|MSTP program, Indiana University School of Medicine, Indianapolis, IN USA.
authors.forename: Melissa
authors.initials: M
authors.lastname: Tully
authors.affiliation: Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907 USA.|Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907 USA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Tang
authors.affiliation: Department of Neurobiology, Fourth Military Medical University, Xi'an, China.
authors.forename: Shengxi
authors.initials: S
authors.lastname: Wu
authors.affiliation: Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907 USA.|Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907 USA.
authors.forename: Riyi
authors.identifier: 0000-0002-7297-9428
authors.initials: R
authors.lastname: Shi
keywords: Acrolein; Axonal membrane damage; EAE; Horseradish Peroxidase; Membrane permeability; Multiple sclerosis; Neurodegeneration; Polyethylene glycol