J Korean Neurol Assoc.  2007 Nov;25(4):535-543.

Treatment with MnTBAP Protects Against Early Nuclear Translocation of Endonuclease G and Reduces Cerebral Infarction after Focal Cerebral Ischemia/Reperfusion in Mice

• Kim HW
• Cho KJ
• Kim HJ
• Cho YJ
• Lee BI
• Kim GW

Abstract

BACKGROUND: Reactive Oxygen Species (ROS) have been implicated in the pathophysiology of brain injury after ischemia/reperfusion. Recently, it has been reported that endonuclease G (EndoG), a mitochondrial protein, is activated by neuronal excitotoxicity and translocated into nucleus inducing apoptosis. However, it is not elucidated whether ROS are involved in the nuclear translocation of EndoG in focal cerebral ischemia/reperfusion in mice. We investigated whether treatment of manganese tetrakis (4-benzoic acid) porphyrin (MnTBAP) protects against early nuclear translocation of EndoG and reduces cerebral infarction after ischemia/reperfusion in mice
METHODS
Adult male mice were subjected to middle cerebral artery occlusion (MCAO) for 60 min, followed by reperfusion. Immunohistochemistry and Western blot analysis for EndoG were performed at various time points after ischemia/reperfusion. Double staining with EndoG and Terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end-labeling (TUNEL) was also performed. MnTBAP was used to determine whether the production of ROS could inhibit translocation of EndoG into the nucleus.
RESULTS
Western blot analysis and Immunohistochemistry of EndoG showed that nuclear EndoG was detected as early as 4 hrs after reperfusion, and mitochondrial EndoG was significantly reduced at the same time. Double staining with EndoG and TUNEL showed a spatial relationship between EndoG expression and DNA fragmentation. MnTBAP-treated mice showed that the translocation of EndoG was attenuated in comparison with the vehicle- treated mice and decreased infarction volume after ischemia/reperfusion.
CONCLUSIONS
MnTBAP reduced the generation of ROS, and inhibited the early translocation of EndoG, which was followed by the reduction of infarction volume in the ischemic brain after ischemia/reperfusion.

Keyword

Endonuclease G; DNA fragmentation; Transient focal cerebral ischemia; MnTBAP

MeSH Terms

Adult
Animals
Apoptosis
Blotting, Western
Brain
Brain Injuries
Cerebral Infarction*
DNA Fragmentation
Humans
Immunohistochemistry
In Situ Nick-End Labeling
Infarction
Infarction, Middle Cerebral Artery
Male
Manganese
Mice*
Mitochondrial Proteins
Neurons
Reactive Oxygen Species
Reperfusion
Uridine Triphosphate
Manganese
Mitochondrial Proteins
Reactive Oxygen Species
Uridine Triphosphate