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(Stroke. 2005;36:2712.)
© 2005 American Heart Association, Inc.
Original Contributions |
From the Department of Neurology and Brain Korea 21 Project for Medical Science, College of Medicine, Yonsei University, Seoul, Korea (B.I.L, G.W.K.); and Department of Neurological Surgery, Neurology, and Neurological Science, School of Medicine, Stanford University, California (P.H.C).
Correspondence to Dr Gyung W. Kim, Department of Neurology, College of Medicine, Yonsei University, 134, Sinchon-dong, Seodaemun-gu, 120-752, Seoul, Korea. E-mail gyungkim{at}yumc.yonsei.ac.kr
Background and Purpose Recently, apoptosis- inducing factor (AIF), a mitochondrial proapoptotic protein, and its nuclear translocation have been reported in caspase-independent neuronal apoptosis. In this study, we investigated the contribution of reactive oxygen species (ROS) to the nuclear translocation of AIF and the subsequent DNA fragmentation after permanent focal cerebral ischemia (pFCI) using manganese tetrakis (4-benzoic acid) porphyrin (MnTBAP), which mimics mitochondrial superoxide dismutase.
Method Adult male ICR mice were subjected to pFCI by intraluminal suture blockade of the middle cerebral artery. Immunohistochemistry and Western blot analysis were performed. Large-scale DNA fragmentation was evaluated by pulse field gel electrophoresis, and apoptotic cell death was quantified. MnTBAP was injected into the ventricle to determine whether the removal of ROS contributes to AIF translocation and the subsequent DNA fragmentation.
Results Western blot analysis showed that the nuclear translocation of AIF occurred as early as 2 hours after pFCI. AIF translocation was not blocked by a pan-caspase inhibitor. MnTBAP-treated mice had attenuated AIF translocation and blocked large-scale DNA fragmentation. Caspase-3 activity was similarly inhibited between the pan-caspase inhibitor and MnTBAP-treated mice, but the amount of apoptosis-associated DNA fragmentation in the MnTBAP-treated mice was less than in the pan-caspase inhibitortreated mice (P<0.001).
Conclusion These results suggest that the MnTBAP, a mitochondrial O2 scavenger, may attenuate the caspase-independent nuclear translocation of AIF after pFCI and subsequent apoptosis-associated DNA fragmentation.
Key Words: antioxidants apoptosis cerebral ischemia, focal mice
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