title: Polyethylene glycol protects injured neuronal mitochondria.
abstract: OBJECTIVE
  Polyethylene glycol (PEG), a hydrophilic polymer, can immediately repair neuronal membranes and inhibit free radical production following trauma. The aim of this study is to examine whether PEG can directly repair mitochondria in the event of trauma.
  
  
  METHODS
  Purified brain mitochondria from guinea pigs were used. Mitochondrial function was assessed by biochemical methods and structural changes were observed by both fluorescence light microscopy and coherent anti-Stokes Raman scattering microscopy.
  
  
  RESULTS
  We present evidence suggesting that PEG is capable of directly reducing injury to mitochondria independent of plasma membrane repair. Specifically, the suppression of oxygen consumption rate of purified mitochondria due to H2O2 and/or calcium can be significantly reversed by 12.5 mM PEG. PEG also significantly reduced mitochondrial swelling due to similar injury. Furthermore, we have shown that such PEG-mediated mitochondrial protection is dependent on the molecular weight of PEG, suggesting a direct physical blockade of mitochondrial permeability transitional pore by PEG.
  
  
  CONCLUSIONS
  These findings, coupled with previous evidence that PEG enters the cytosol following mechanical trauma, strongly indicate that there are at least 2 avenues of PEG-mediated cytoprotection in mechanically injured spinal cords: repair of plasma membrane and protection of mitochondria.
authors.affiliation: Department of Basic Medical Sciences, Center for Paralysis Research, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Haiping
authors.initials: H
authors.lastname: Chen
authors.forename: Eamon
authors.initials: E
authors.lastname: Quick
authors.forename: Gary
authors.initials: G
authors.lastname: Leung
authors.forename: Kristin
authors.initials: K
authors.lastname: Hamann
authors.forename: Yan
authors.initials: Y
authors.lastname: Fu
authors.forename: Ji-Xin
authors.initials: JX
authors.lastname: Cheng
authors.forename: Riyi
authors.initials: R
authors.lastname: Shi
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D005260:Female; D006168:Guinea Pigs; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D008928:Mitochondria / Q000187:drug effects* / Q000473:pathology; D009474:Neurons / Q000187:drug effects* / Q000473:pathology; D018696:Neuroprotective Agents / Q000494:pharmacology*; D010101:Oxygen Consumption / Q000187:drug effects; D011092:Polyethylene Glycols / Q000494:pharmacology*
chemical_list: D018696:Neuroprotective Agents; D011092:Polyethylene Glycols