Manganese Superoxide Dismutase Affects Cytochrome c Release and Caspase-9 Activation After Transient Focal Cerebral Ischemia in Mice

J Cereb Blood Flow Metab. 2001 May;21(5):557-67. doi: 10.1097/00004647-200105000-00010.


Release of cytochrome c from mitochondria to cytosol is a critical step in the mitochondrial-dependent signaling pathways of apoptosis. The authors have reported that manganese superoxide dismutase (Mn-SOD) attenuated cytochrome c release and apoptotic cell death after focal cerebral ischemia (FCI). To investigate downstream to the cytochrome c-dependent pathway, the authors examined caspase-9 activation after transient FCI by immunohistochemistry and Western blotting in both wild-type and Sod2 -/+ mice. Mice were subjected to 60 minutes of middle cerebral artery occlusion followed by 1, 2, 4, or 24 hours of reperfusion. Two hours after reperfusion, cytochrome c and caspase-9 were observed in the cytosol and significantly increased in Sod2 -/+ mutants compared with wild-type mice as shown by Western blotting. Immunofluorescent double labeling for cytochrome c and caspase-9 showed cytosolic cytochrome c 1 hour after transient FCI. Cleaved caspase-9 first appeared in the cytosol at 2 hours and colocalized with cytochrome c. Terminal deoxynucleotidyl transferase-mediated uridine 5;-triphosphate-biotin nick and labeling (TUNEL) showed significant increase of positive cells in Sod2 -/+ mice compared with the wild-type in the cortex, but not in the caudate putamen. The current study revealed Mn-SOD might affect cytochrome c translocation and downstream caspase activation in the mitochondrial-dependent cell death pathway after transient FCI.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Apoptosis
  • Blotting, Western
  • Brain / enzymology*
  • Brain / ultrastructure
  • Caspase 9
  • Caspases / metabolism*
  • Cytochrome c Group / metabolism*
  • Cytosol / metabolism
  • DNA Fragmentation
  • Enzyme Activation
  • Fluorescent Antibody Technique
  • Immunohistochemistry
  • In Situ Nick-End Labeling
  • Ischemic Attack, Transient / enzymology*
  • Ischemic Attack, Transient / pathology
  • Mice
  • Mice, Knockout
  • Mitochondria / metabolism
  • Superoxide Dismutase / deficiency
  • Superoxide Dismutase / genetics
  • Superoxide Dismutase / physiology*


  • Cytochrome c Group
  • Superoxide Dismutase
  • Casp9 protein, mouse
  • Caspase 9
  • Caspases