Polyethylene glycol protects injured neuronal mitochondria.
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.
Chen
Haiping
H
Department of Basic Medical Sciences, Center for Paralysis Research, Purdue University, West Lafayette, Indiana 47907, USA.
Quick
Eamon
E
Leung
Gary
G
Hamann
Kristin
K
Fu
Yan
Y
Cheng
Ji-Xin
JX
Shi
Riyi
R
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*
D018696:Neuroprotective Agents; D011092:Polyethylene Glycols